We recently ran into this issue:
When the same certificate is used for multiple Load Balancers on the same VIP (IP), and different TLS Security Levels are configured between these Load Balancers, they are not enforced.
We would like a warning message indicating that the enforcement may not take place, and reference to docs describing the issue.
It was very annoying to change the setting, and without warning, the setting did not take effect. Had to open a case to find out why.