Content Monitor version is 4.8.
I'm seeing the problem more on my 12.1.2015.2015 SEPM, but see 1 or two on my SEP 11 server also.
I searched for duplicate entries on the SEPM and there are none. The SEPM shows the client is up to date.
As to the question of a re-install being done, that is probable, particuarly on the SEP 12 server where I see most of the duplicates. I am migrating clients from SEP 11 to SEP 12 slowly (location by location) and clients are being upgraded to the new version as part of that process.