macOS menu bar appearing in Full Screen mode after updating to PD 26.2.1

I've just updated to PD 26.2.1 on my 2019 Intel-powered iMac. I have Parallels running in Full Screen mode on my second monitor.

Following the update, the macOS menu bar appears at the top of this second monitor whenever I move the focus to my main monitor; as soon as I switch focus back to Parallels, the macOS menu bar disappears. (Actually, it's a bit more complicated than that: if focus is with an app on my main monitor and I Cmd-Tab to switch it back to Parallels, the menu bar stays visible until I move the mouse pointer back over the Parallels screen, at which point the menu bar disappears. I don't have to click anywhere inside Parallels - provided focus is with Parallels, just moving the mouse pointer to the Parallels screen is enough to make the menu bar at the top of this screen disappear.)

"Optimise full screen for games" is already selection in Configuration > Options.

I've been using PD in Full Screen mode for well over a decade, and the OS menu bar has never behaved this way: it's always been hidden.

This is an extremely irritating change and I'd like to know whether it's a bug (in which case when can I expect it to be fixed?) or whether there's something I can do to remedy it.

Thanks in advance

 

Update: exiting full screen mode and then immediately re-entering it appears to have fixed the problem.