You can use the attached blueprint setup to reproduce. The Player Controller has “Show Mouse Cursor” enabled.
The game starts with free mouse look. The idea is, K disables mouse look and RMB release enables it. However, if you press K 4 times, you will need to press RMB 4 times in order to get mouse look back.
Thanks for the report! I was able to reproduce this issue, and have entered a bug report for the developers to look over (UE-7141). I’m not certain if we’re understanding this node’s functionality correctly, but I will let you know what they say. In the meantime, a simple Branch check should be all you need to get around this issue:
Hope that helps!