[Stable Update] 2021-02-28 - Kernels, Plasma 5.21.1, Frameworks 5.79, Firefox, Thunderbird, Python

Hi,
with this update, this bug is still present:

This solution doesn’t work:

Can someone help me? I think I have to downgrade something, but I don’t know what exactly. @philm Is there a specific package related to the opening of externals links in GTK?