QDialog::move() not considering taskbar on Ubuntu with multiple screens

Normally, moving a QDialog using QDialog::move() positions the dialog outside of taskbars. However, on Ubuntu 20.04 with two monitors it is not the case with frameless Dialogs : the move() call can move it inside the taskbar :

This does not happen if the dialog is not frameless :

This behaviour has been observed on Ubuntu 20.04. It also happens only under some configurations :

• Main monitor needs to be on the right side, with task bar on the left (between the two monitors)
• Left monitor needs to have a lower resolution than the right one
• Fractional scaling needs to be disabled

A minimal reproducible example is attached.