It shoud be problem with VSE 8.8.
Actually it was resolved in VSE 8.7 patch 4
Not sure , just remove and reinstall VSE 8.7 on one machine and check.
Do you see more tan an icon even after a reboot? Have you ever installed a VSE 8.8 trial on these machines?
I will try to go back to vse 8.7 and see what happen, thanks for your help.