I have phones where the message waiting light are lit but there are no messages in the mailbox. Not sure but it looks like the lights are flashing more rapidly then a message waiting light.
Anyone Know why or how to shut them off.

Which system SV8100 or SV8300?

DrPbx, can he go off hook and dial 620 to get the flashing light to go away..I had the same issue once

In that case it's not from the voicemail but an MWI set by another user. i.e. dialing a station then pressing zero will set a MWI 620 will cancel it..

Thanks it was a mw light