I'm almost hesitant to say anything else regarding xfwm4, since I don't want to derail this bug report. However, if it saves you the effort of potentially downgrading/reinstalling your system, then you might want to try enabling compositing with xfwm4: Run xfwm4-tweaks-settings, click the 'Compositor' tab, and select 'Enable display compositing'.
I'm almost hesitant to say anything else regarding xfwm4, since I don't want to derail this bug report. However, if it saves you the effort of potentially downgrading/ reinstalling your system, then you might want to try enabling compositing with xfwm4: Run xfwm4-tweaks- settings, click the 'Compositor' tab, and select 'Enable display compositing'.