Like ForceRefTo, Clear also causes EvaluatePackage for that Actor. This was not documented. (Now updated.)

However, unlike ForceRefTo, I've been unable to confirm that it causes EvaluatePackage for ALL actors in a scene. Which might be a good thing, but is anybody else able to check this?

A problem is that Clear is usually in a script fragment from a package on the actor. This can result in 2 script fragments running in parallel, and in my cases caused a contention problem.

I'd thought I'd read somewhere that only 1 package would run at a time on a given actor. I'd assumed the game engine had an interlock that prevented the new package from running until all the script fragments for the old package had completed. Apparently not!!!

Anyway, I've verified that when 2 packages are running at the same time on the same actor, and you try to save, it causes a CtD. You have to wait for both package script fragments to run to completion, or ensure that the second package has no scripts. (I used DoNothing.)