Hey guys 
Yeah, I thought that was fixed, obv. it wasn’t :-/
Anyways, a quick workaround to this is, to just use a “normal” build from the engine, and not building an own one with the UAT extension (or delete the UAT extension if you need to build your own engine for other reasons).
The only thing this will affect is the “Package Mod” option in the editor - it’ll just not do anything, then, but everything else will work, incl. testing mods from the editor, so you should be able to continue your work, at least.
My plan is to replace the UAT call “Packege Mod” makes with ones that work with vanilla/unmodified UAT and therefore removing the need for a sourcebuild of the engine alltogether, which will get rid of this problem.
Just need to find some time to sneak away from work to implement it, I’m fairly confident I found a set of nicely working UAT calls.
Sorry for the troubles.