If I collapse nodes in a blueprint I can’t play in the editor, standalone play will however work. I’m not sure if this is a general bug or if it’s only caused by certain nodes.
Thank you for your report. We were not able to investigate this on the engine version you reported, but there have been many version changes to UE4 since this question was first posted. With a new version of the Engine comes new fixes and it is possible that this issue has changed or may no longer occur. Due to timetable of when this issue was first posted, we are marking this post as resolved for tracking purposes.
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