What does it mean when there shows "warning solar panels over voltage" on the controller?

What does it mean when there shows "warning solar panels over voltage" on the controller?

Q: My solar controller shows: "warning solar panels over voltage" , but I'm sure the solar panel is not over voltage.

A: The warning will be shown when the battery is almost full or in full situation, you can ignore it if the controller is still in working condition.
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