Let's try turning Groupy2 off and see if it is actually causing this issue, or if it's something else.
Are you using autohide for the taskbar?
Is you taskbar at the top or bottom?
If I had your Start11v2 settings, I could try to reproduce your issue. If you are willing, make a Settings backup file using Start11v2 and post a link here or PM me with a link. I'll use your Settings backup to configure Start11v2 on my system and see if I get the same results.
And, I have to ask if you are using any other software to alter the taskbar?