QT tab widget does not work on maint-3.8 (ubuntu 20.04)

I just tested a simple QT tab widget with two tabs and it does not run on maint-3.8

Attached please see the example giving the following error (at the end of the email)

Can someone verify this is indeed the case?

thanks 

Achilleas

File "/n/girard/x/anastas/GNURADIO_LAB/test_tabs.py", line 169, in main
    tb = top_block_cls()
  File "/n/girard/x/anastas/GNURADIO_LAB/test_tabs.py", line 128, in __init__
    self.mytab_layout_0.addWidget(self._qtgui_time_sink_x_0_win)
  File "/usr/local/lib/python3/dist-packages/gnuradio/gr/hier_block2.py", line 93, in __getattr__
    return getattr(self._impl, name)
AttributeError: 'top_block_sptr' object has no attribute 'mytab_layout_0'

>>> Done (return code -11)