Upgrade to Thinos 2402 for Optiplex 3040 causing problems

Hi,  We have recently started upgrading our 3040's to the latest available ThinOs 2402 but we have hit a few problems which we have only been able to narrow down to the thin OS upgrade. on some of the terminals, the keyboards will stop working while in use and require the USB connection removed and connected again for it to start working again.  In another case, the resolution is reduced on a second monitor and only resolved when the terminal is reset. i Have tried the upgrade via the WMS console and rebuilding from a USB but the problems still occur, i have looked through the settings applied but i'm not seeing anything that could cause this. does anyone have any suggestions as i'm running out of ideas?