Quick answer: Unreal Blueprint collapsed graph node showing broken connections after the underlying function is renamed? Collapsed nodes cache function name strings - re-collapse or restore via the references.
Renamed a custom function called inside a collapsed graph. Collapsed node now shows red lines.
Re-collapse
Expand the collapsed node; re-collapse. New collapse picks up the new function name.
Or rename via IDE refactor
Rider/VS refactor updates Blueprint references where possible. Manual rename breaks them.
Audit collapsed nodes
Find > Find in Blueprints. Discover all collapsed graphs; recheck for broken references post-refactor.
“Blueprint nodes can hold cached strings. String renames need explicit migration.”
Avoid collapsed graphs for hot-iteration code. Re-collapse cost compounds; the convenience is shallow.