Extra clefs appearing when applying Mensurstrich

I see that some problems with manipulating barlines have been reported, not sure if this one is already known.

I created a score with three instruments Voice and changed to a bass clef for each stave. So far so good (attachment stage1.mscz). Then I created Mensurstriche by editing the properties of the barlines in the inspector: for the top two staves, I ticked "Span to next stave" and set "Span from" to 8, for the bottom stave I unticked "Visible". The result looked OK, but after saving and reopening the file, the bottom two staves showed an extra clef after the time signature (attachment stage2.mscz).

The same problem did not occur when I started with three instruments Bass (that, notably, have the bass clef as default). Btw, that doesn't solve my actual problem which has Tenor instruments with C4 clefs etc.

I am using MuseScore version 3.0.2.5315 under Windows 10 Home.

Thanks!
Nynva