What steps will reproduce the problem?

Nameplate of palyer and mobs both have this problem.

What version of ShestakUI are you using? (Stating 'latest' is not useful)

0.88

Do you have an error log of what happened?

no

Any additional information? (example: WoW language if not English) (Attach screenshots here if available, do not link externally)

This isn't a bug, but rather intended. When the target has the same level as you (the player), it won't show. It only shows for lower levels and higher levels. This is mainly intended for when max level to avoid unnecessary information.