Does the program stop executing? Or it keeps running until a restart of the PLC is triggered, by for example a power failure. And only after a restart, a new 7-day trial license needs to be generated?
I have had prototype / R&D equipment running with trial license for weeks or so. In my experience, nothing happens when 7 days has passed.
But if you reboot the PC or restart TwinCAT runtime (or update software), it won't start again. Instead, TwinCAT runtime just stays in Config mode and requires new trial license before setting it to run mode again.
Edit: This is also confirmed by Beckhoff staff, see comment below.