This issue has been annoying me for a while now and stretches back several months, if not longer.
Once in a while, when I use Command"z" to go a few steps back, I end up with objects and text being grouped that were never grouped in the first place. Most of the time, the issue somehow resolves itself after I randomly select some other objects outside of this newly formed "group". Still, it`s a big time waste.
That`s a valid point you're making there, Monika. I haven`t checked in the layers panel if those objects are really grouped or just selected together. I guess they are selected together, but nevertheless, it takes a while for them to deselect again.
Yes, this can affect your workflow in very bad ways. This seems to be difficult to locate and thus has not been solved. I cannot find a report on Illustrator uservoice (the bug tracking site). https://illustrator.uservoice.com You could search the site again and then support a bug report or just report it there yourself in order to try and get it solved.
I assume that you have already tried rebooting the computer and resetting the preferences.