Node trees have to be updated after remapping IDs in the node tree. This will,
among other things, create/delete sockets on group nodes. Furthermore, this also
tags the depsgraph so that objects that (indirectly) depend on the node group
output are reevaluated.
The tagging of node trees to update already happens in
`foreach_libblock_remap_callback_apply` for a while, the issue is that the
actual propagation of tagged changes does not happen currently.
I was checking this because Simon ran into some bug after deleting libraries. He
couldn't reproduce it anymore, but my best guess right now is that it is caused
by a missing update.
Pull Request: https://projects.blender.org/blender/blender/pulls/124980
8bf8542ffe