Configuration UI Package 1.10.275 breaks GUI unresponsive

On Dell Wyse Management Suite 4.1 or 4.2, as soon as I import Config UI Package 1.10.275, the Webinterface freezes when I enter the Configuration section:

ThinOS 9.x -> Firmware -> Application Package Updates

There appears a black spinning wheeel, the GUI never finishes loading, and everything stops responding. This triggers 100% of the time, as soon as I enter that GUI section. Every other window still works.

I can reproduce this after a VM restore and a re-import of DellWMS-ConfigurationUI-Package.zip

AFAIK config UI packages are not downgradeable so all I can do is restore the VM.