Yes it is, thank you so much, I can change the setting now and it works fine.
In case this is important for future bug reporting, the issue is slightly different for me than is described in that issue log (though I did only skim read it). It seems the issue they were working on was only found when accent or highlight colour was set to graphite, whereas for me it happens on any accent colour.
I had dark mode with multicolour accent selected. The issue also only happens if I select Light mode in LibreOffice (I have now changed it to “system”, which works fine).
To test this, I changed the accent to graphite and switched LibreOffice to Light again, and the same issue appeared. So I tried using accent colours purple and green, and the same thing.
So this is fine for me now, I can use it, but the issue is still there (and I can’t use Light mode without changing my system settings, of course).
Thanks again, very much appreciated.