All critical bugs have been fixed and as it turned out it were seemingly two Unreal Engine related bugs that have hit us.
It was a misbehaving Find node for string arrays that always returns false but only when executed in a packaged game. Another bug was that the Remove (string) by Element node also did not function properly when executed in a packaged game. I replaced the Find node with my own implementation and for the Remove by Element node I used the Remove by Index node instead to fix those critical bugs that prevented our game from functioning normally.
As soon as we are allowed to update the executable, we will make sure to upload the fixed version.