Best posts made by Ant1

@Ant1 We realized that after putting the U axis under tension using M17 U, there is an interference between the BL Touch's ground and the U motor phases... So we are now investigating this issue. So I think that the issue doesn't come from the firmware, so I guess we can close this topic and we will test our setup on our side... Thank you very much for your help !!

@chrishamm @stuartofmt I also find a bit dangerous / weird to use exec(...) to compare the versions, as it can very easily lead to code injection, even though it is probably not the intent of people writing plugins.
Edit: the allowed characters are limited (for example, no parentheses), so this is probably not possible.

@chrishamm Thanks a lot, that was the problem ! I was looking at an old documentation page that didn't show that this permission was possible... Thank you !

@chrishamm Okay thanks for all the pointers ! I switched all my machines to 3.5.3 and made the changes with the connections that you suggested, and it solves most of my problems.

For the problem that I mentionned due to the machine being shifter along the Z axis after executing a macro from the plugin, I found something that might have caused the issue:

When intercepting a command inside the plugin, I was always starting by sending G90 and M83 to the machine to make sure that whatever mode it is in, I can always perform moves and extrusions in absolute and relative mode, respectively. I suspect that those two commands might have caused the machine to shift position along Z due to synchronization issues because I removed them and the issue never happened again...