Has anyone encountered the following scenarios in v5.1.9:-
This is getting quite frequent and beginning to be annoying.
Are your key sizes for both users and machines set to 256?
Have you recently changed your key sizes? If a machine was encrypted with key sizes of 64 and then you changed the key sizes to 256 i can see this error happening because the machine would still be looking for only 1 line of code at 64 key size and the database thinks it should see 4 lines of code due to the 256.
actually, the key size is always the alg max length, but the client challenge (and the setting) indicates how much of the key the response should use, to prevent the situation you mentioned.