Yes, saw that with some of my MR55 as well.
As I was told they will work in a reduced way but had issues I opened a SUPPORT case and was told. that the MR45 and MR55 are not working in 802.3af and would have strange behaviour.
I was also told to have the latest version of software running on it too.
So in short you need 802.3at as per the datasheet ... unfortunately.