I have fixed the loading bug, it was caused by me starting this as a modification of original mod, so the last thing I did was renamed it and forgot to change the lua.
I tested the mod on both a new save and as a replacement of original (I added a migration for it) and both construction and repair work for me
@stef77 did you try on a new save or on previous ones? If on previous, please get the new version and try reloading and do /rt_rescan