Autodeploy and Rebuild dockerfile not using last version

[Fabback]

Hi,

I have 2 problems related to deployment, or at least updates, for a NextJs app (v15).

[Configuration context] :

• 1 dokploy server (from which I manage target servers)
• 1 "cloudflared" server (to which public applications are deployed)
• Github repo is private

First, I followed the simple Github deployment with Nixpacks, and tried that auto-deploy feature. It is explained as working out of the box with no further configuration, but doesn't seem to be detecting changes published to Github, and I don't see any log of it being deployed. On the other hand Webhook URL are for Github, Gitlab...
So is it an out of the box, but you must call webhook, or did I miss some configuration ? (The check mark is appearing on "autodeploy" but is it when it is "on" OR "selectable" ??? the notification just tels me the value is changed, no further indication)
The only successful way I found was to manually hit "Rebuild" ...

... until second problem arises :
I just changed my NextJs to be a "standalone" deployment, therefore I created my own dockerfile, changed the buildtype accordingly. At first it pulled the dockerfile from github, but stopped on an error (my bad, I was copying the "public" folder when there wasn't any...). I corrected the error, synced the file to my repo, and now not matter what it doesn't use the corrected "dockerfile" and I'm stuck with the project still using the last version of the file and erroring without trying to rebuild the image.

EDIT : I reverted back to a nixpacks and removed the "standalone" NextJs value while awaiting for an eventual response, it doesn't seem to sync my Github anymore

Thanks for your help, sorry for the chaotic message, it reflects my level of comprehension as of today