QUiLoader resolves wrong QLabel buddy

When loading the ui-file in 2 different widgets having the same parent resolving a
buddy-widget for a label goes wrong.

When the file is loaded for the second widget the buddy resolved is
pointing to the line-edit created in when the ui-file was loaded first.

Current Work-around

Use the QUiLoader::load() method without a parent (nullptr) a
nd setting the parent to the widget afterwards.

Personal Remarks

This is not the expected behavior or I must be mistaken.
The buddy resolving mechanism should limit itself to the widgets created
in the current loaded ui-file only like in Qt Designer application.

I added a single file with single function which illustrates the "bug".
It can easily be added to a unit testing environment.