I too have faced the similar problem but luckily not in Production system (Enhanced screen not transported to Production as of now. Need to check the behavior after transporting).
Though the exact reason is unknown (at least for me), I have temporarily resolved by changing the SAP GUI theme.
I am facing the problem with 'Enjoy Theme' but when changed to 'SAP Signature theme' then Restart the system (not SAP Logoff, restarting the whole system), then it is working fine for me. I can see the full screen without any cuts.
Please check if it is the case for you and share your findings.