acejavelin,
I am not sure as we don't install new MiVO-250's anymore, but do you have extended message print turned on?
Most likely they haven't thought to provide a way to remove that from the logs, but if they did I would think it would be under Maintenance; if I had to guess.
Maybe it is because you have the CESID Assignment set to Automatic under the phones; try Emergency CPN if you don't want it to be auto assigned.
Thanks,
TE