I've been having this problem, too, on AutoCAD Map 2016. One work around is to change the Quick Leaders to Annotative, edit them, then change back.
Like you, I also use KeySoft's KeySign package, so maybe that's a clue. I've seen it altering file paths of another instance of AutoCAD running at the same time.
I noticed today that a drawing with Quick Leaders was initially fine but about 2 hours later, in the same drawing session, the Quick Leaders lost their grips.
I suspect that this isn't a setting saved in the drawing which is why other contributors here couldn't see a problem with a posted file.
I tried comparing system variables between the two states. Only two differences were noted and not significant. I don't know how thorough this Express Tool is though. It didn't list STATUSBARAUTOWRAP, for example.
I'm trying to spot what triggers the behaviour change. It could be a loooong time.