At a quick glance I think you are running into an infinite loop here because you have no way to stop jumping based on what I see here. The stop jumping node is not connected so that could be causing some problems.
Could you provide me with your project that is having this issue so I can troubleshoot with that. When creating a fresh project I am getting the error but I am not getting a crash.
If I use another name for the Interface function no loop occurs and the character jumps properly so I think it’s just an issue with duplicate names.
I’ve only used the third person template with nothing else in it.
Then I would expect the editor not to compile this blueprint like it does if a blueprint function or custom event has the same name so there is no chance for undefined behaviour.
This only happens with inherited functions without any input and output.
Anyway, I’ve attached a recording of the bug and the crash. crash