Some of the air-cooled Monsters had defective oil temperature sensors, but it seemed to be confined to a batch of 620's.
A couple months back there were some posts on the oil temp reading 150 or so, immediately after turning the key on after the bike sat all night. IIRC, all of those folks got the sensors replaced under warranty, and I haven't read any more posts on it.
Oil temp over 212 is good, so it'll evaporate off any water from combustion blowby or crankcase condensation. For petroleum oil, I recall seeing that 250 or so is about the max that the manufacturers recommend.
Some of our folks here race their 620's, and have reported oil temps up around 300. From what I've seen published, that's really hard on petroleum oil.