As I told at this point only one thread exists. And yes, I'm using threads but not at this point of initialization.
Well, with threads its often the case, that we THINK we are doing X, but after carfully inspecting the code, we discover that we are actually doing Y.
So I think it would be best if you would post relevant code segments (where the ui is initialized, and your thread initializtion).
I think the problem is more that my program is statically linked and tries to load the "imageformat/qjpegd.dll". So maybe the warning reason is because of something done in the qjpegd.dll? The object which tries to be moved is the QObject returned by the QPluginLoader::instance()-call.
Possible, but not likely, since then it would always be the case, for other users as well.
It is easy to test though - make a dummy project, no threads, make a simple ui with the widget you are using and see if this still happens.

But as I said, code segment would help much more.