diff --git a/easybuild/easyblocks/generic/bundle.py b/easybuild/easyblocks/generic/bundle.py
index 23da2338c2d..b8abecf8fc0 100644
--- a/easybuild/easyblocks/generic/bundle.py
+++ b/easybuild/easyblocks/generic/bundle.py
@@ -85,6 +85,10 @@ def __init__(self, *args, **kwargs):
             if self.cfg['patches']:
                 raise EasyBuildError("List of patches for bundle itself must be empty, found %s", self.cfg['patches'])
 
+        # copy EasyConfig instance before we make changes to it
+        # (like adding component sources to top-level sources easyconfig parameter)
+        self.cfg = self.cfg.copy()
+
         # disable templating to avoid premature resolving of template values
         self.cfg.enable_templating = False
 
diff --git a/easybuild/easyblocks/generic/cargo.py b/easybuild/easyblocks/generic/cargo.py
index c49e950969b..d03407862db 100644
--- a/easybuild/easyblocks/generic/cargo.py
+++ b/easybuild/easyblocks/generic/cargo.py
@@ -151,6 +151,9 @@ def __init__(self, *args, **kwargs):
                     'filename': self.crate_src_filename(crate, version),
                 })
 
+        # copy EasyConfig instance before we make changes to it
+        self.cfg = self.cfg.copy()
+
         self.cfg.update('sources', sources)
 
     @property