Very wierd display problem

I have created a powershell script that flips between three PowerBi dashboards displayed on a large screen on our office - each dashboard is displayed for 30 seconds before switching to the next - a carousel display so tthe people in the office can get a quick look at current data from their desks.

This was working fine on an old Win7 PC we were using, but that was scrapped and it was replaced with a new mini PC running Win 10.

After an indeterminate period of time, the display corrupts, with a huge PowerBi toolbar taking up the whole screen - see below:

To get it working again I have to close all windows and the powershell screept, then restart it.

Has anyone seen this before?  If so is there a fix or workaround?