Quick answer: Unreal Anim Blueprint pin connections vanishing after promoting a value to a variable? Promotion can change pin types; cosmetic mismatch breaks the wiring - manually reconnect.
Right-clicked a value, promoted to variable for reuse. Anim graph nodes downstream now show broken pins.
Reconnect manually
Inspect each broken pin. Drag from the variable to the consumer. Type-compatibility issues surface as red lines.
Verify types match
Promotion to a higher-precision type (float -> double) silently breaks. Use the exact type the consumer expects.
Or undo and retry
Sometimes the simplest. Undo; promote into a different namespace; retry with clean state.
“Promote-to-variable is a transformation. Transformations have edge cases.”
Save before refactoring Anim BPs. The Anim graph is brittle; backups are cheap.