diff --git a/cmd/ddev/cmd/addon-get_test.go b/cmd/ddev/cmd/addon-get_test.go
index 5f8e1ddc0b1..063b34c63a6 100644
--- a/cmd/ddev/cmd/addon-get_test.go
+++ b/cmd/ddev/cmd/addon-get_test.go
@@ -185,7 +185,7 @@ func TestCmdAddonGetWithDotEnv(t *testing.T) {
 	busyboxEnvFile := filepath.Join(site.Dir, ".ddev/.env.busybox")
 	require.NoFileExists(t, busyboxEnvFile, ".ddev/.env.busybox file should not exist at this point")
 
-	out, err = exec.RunHostCommand(DdevBin, "dotenv", "set", ".ddev/.env.busybox", "--busybox-tag=1.36.0", "--pre-install-variable=pre", "--pre-install-variable2=pre2", "--post-install-variable", "post", "-A", "short_flag_VALUE", "--force-run", "-yes", "--force-UPPERCASE=true")
+	out, err = exec.RunHostCommand(DdevBin, "dotenv", "set", ".ddev/.env.busybox", "--busybox-tag=1.36.0", "--pre-install-variable=pre", "--pre-install-variable2=pre2", "--post-install-variable", "post", "--force-run")
 	require.NoError(t, err, "out=%s", out)
 	out, err = exec.RunHostCommand(DdevBin, "add-on", "get", filepath.Join(origDir, "testdata", t.Name(), "busybox"))
 	require.NoError(t, err, "out=%s", out)
@@ -204,10 +204,6 @@ func TestCmdAddonGetWithDotEnv(t *testing.T) {
 	require.Contains(t, string(busyboxEnvFileContents), `POST_INSTALL_VARIABLE="post"`)
 	// --force-run is converted to empty string
 	require.Contains(t, string(busyboxEnvFileContents), `FORCE_RUN=""`)
-	// Some flags are ignored because they should not contain uppercase, or be a wrong flag:
-	require.NotContains(t, string(busyboxEnvFileContents), `A="short_flag_VALUE"`)
-	require.NotContains(t, string(busyboxEnvFileContents), "YES")
-	require.NotContains(t, string(busyboxEnvFileContents), "FORCE_UPPERCASE")
 
 	out, err = exec.RunHostCommand(DdevBin, "add-on", "get", filepath.Join(origDir, "testdata", t.Name(), "bare-busybox"))
 	require.NoError(t, err, "out=%s", out)
diff --git a/cmd/ddev/cmd/dotenv-get.go b/cmd/ddev/cmd/dotenv-get.go
index 64d9986def2..15311fdc836 100644
--- a/cmd/ddev/cmd/dotenv-get.go
+++ b/cmd/ddev/cmd/dotenv-get.go
@@ -54,7 +54,10 @@ ddev dotenv get .ddev/.env.redis --redis-tag`,
 		}
 
 		// Get unknown flags and ensure only one flag is passed
-		envFlags := GetUnknownFlags(cmd)
+		envFlags, err := GetUnknownFlags(cmd)
+		if err != nil {
+			util.Failed("Error reading command flags: %v", err)
+		}
 		if len(envFlags) < 1 {
 			_ = cmd.Help()
 			return
@@ -69,7 +72,7 @@ ddev dotenv get .ddev/.env.redis --redis-tag`,
 		}
 
 		if !strings.HasPrefix(flag, "--") {
-			util.Failed("The flag must be in a long format.")
+			util.Failed("The flag must be in long format, but received %s", flag)
 		}
 
 		// Extract the environment variable name
diff --git a/cmd/ddev/cmd/dotenv-set.go b/cmd/ddev/cmd/dotenv-set.go
index 85ed6e4d078..64c766ea3a5 100644
--- a/cmd/ddev/cmd/dotenv-set.go
+++ b/cmd/ddev/cmd/dotenv-set.go
@@ -63,7 +63,10 @@ ddev dotenv set .ddev/.env.redis --redis-tag 7-bookworm`,
 		}
 
 		// Get unknown flags and convert them to env variables
-		envSlice := GetUnknownFlags(cmd)
+		envSlice, err := GetUnknownFlags(cmd)
+		if err != nil {
+			util.Failed("Error reading command flags: %v", err)
+		}
 		hasUnknownFlags := false
 		changedEnvMap := make(map[string]string)
 		for flag, value := range envSlice {
@@ -72,6 +75,8 @@ ddev dotenv set .ddev/.env.redis --redis-tag 7-bookworm`,
 				envMap[envName] = value
 				changedEnvMap[envName] = value
 				hasUnknownFlags = true
+			} else {
+				util.Failed("The flag must be in long format, but received %s", flag)
 			}
 		}
 
diff --git a/cmd/ddev/cmd/dotenv_test.go b/cmd/ddev/cmd/dotenv_test.go
index fe2a5897ff8..12962468af0 100644
--- a/cmd/ddev/cmd/dotenv_test.go
+++ b/cmd/ddev/cmd/dotenv_test.go
@@ -75,6 +75,18 @@ func TestCmdDotEnvGetAndSet(t *testing.T) {
 	require.Error(t, err, "out=%s", out)
 	require.Contains(t, out, "The file should have .env prefix")
 
+	out, err = exec.RunHostCommand(DdevBin, "dotenv", "set", envFile, "-a", "custom value")
+	require.Error(t, err, "out=%s", out)
+	require.Contains(t, out, "flag must be in long format")
+
+	out, err = exec.RunHostCommand(DdevBin, "dotenv", "set", envFile, "--TEST", "custom value")
+	require.Error(t, err, "out=%s", out)
+	require.Contains(t, out, "the flag must be lowercase and start with a letter")
+
+	out, err = exec.RunHostCommand(DdevBin, "dotenv", "set", envFile, "--1test", "custom value")
+	require.Error(t, err, "out=%s", out)
+	require.Contains(t, out, "the flag must be lowercase and start with a letter")
+
 	out, err = exec.RunHostCommand(DdevBin, "dotenv", "get", envFile, "--test-value", "--test-value-2")
 	require.Error(t, err, "out=%s", out)
 	require.Contains(t, out, "one environment variable can be retrieved at a time")
@@ -85,7 +97,7 @@ func TestCmdDotEnvGetAndSet(t *testing.T) {
 
 	out, err = exec.RunHostCommand(DdevBin, "dotenv", "get", envFile, "-a")
 	require.Error(t, err, "out=%s", out)
-	require.Contains(t, out, "flag must be in a long format")
+	require.Contains(t, out, "flag must be in long format")
 
 	out, err = exec.RunHostCommand(DdevBin, "dotenv", "set", envFile, "--test-value-with-special-characters", `Test$variable\nwith\n_new_lines`)
 	require.NoError(t, err, "out=%s", out)
diff --git a/cmd/ddev/cmd/utils.go b/cmd/ddev/cmd/utils.go
index 469542aec2b..8053b0edc01 100644
--- a/cmd/ddev/cmd/utils.go
+++ b/cmd/ddev/cmd/utils.go
@@ -92,10 +92,10 @@ func getRequestedProjectsExtended(names []string, all bool, withNonExisting bool
 // Works only with this config in Cobra: FParseErrWhitelist: cobra.FParseErrWhitelist{UnknownFlags: true}
 // If Cobra implements handling of unknown flags, this function can be removed/refactored.
 // See https://github.com/spf13/cobra/issues/739
-func GetUnknownFlags(cmd *cobra.Command) map[string]string {
+func GetUnknownFlags(cmd *cobra.Command) (map[string]string, error) {
 	unknownFlags := make(map[string]string)
 	if len(os.Args) < 1 {
-		return unknownFlags
+		return unknownFlags, nil
 	}
 
 	// Known flags tracking
@@ -116,8 +116,17 @@ func GetUnknownFlags(cmd *cobra.Command) map[string]string {
 	args := os.Args[1:]
 	for i := 0; i < len(args); i++ {
 		arg := args[i]
-		// Skip if the argument is not a valid flag or a known flag
-		if !flagRegex.MatchString(arg) || knownFlags[arg] {
+		// Skip if the value is a known flag
+		if knownFlags[arg] {
+			continue
+		}
+
+		if !flagRegex.MatchString(arg) {
+			// Fail if the value is not a valid flag
+			if strings.HasPrefix(arg, "-") {
+				return unknownFlags, fmt.Errorf("the flag must be lowercase and start with a letter, but received %s", arg)
+			}
+			// Skip if the value is not a flag, but an argument
 			continue
 		}
 
@@ -134,5 +143,5 @@ func GetUnknownFlags(cmd *cobra.Command) map[string]string {
 			unknownFlags[arg] = ""
 		}
 	}
-	return unknownFlags
+	return unknownFlags, nil
 }
diff --git a/pkg/appimport/appimport.go b/pkg/appimport/appimport.go
index 8e1af785456..114551a1350 100644
--- a/pkg/appimport/appimport.go
+++ b/pkg/appimport/appimport.go
@@ -39,7 +39,7 @@ func ValidateAsset(unexpandedAssetPath string, assetType string) (string, bool,
 	}
 
 	for _, ext := range extensions {
-		if strings.HasSuffix(assetPath, ext) {
+		if strings.HasSuffix(assetPath, "."+ext) {
 			return assetPath, true, nil
 		}
 	}