Actually, this does not surprise me as the FBI director is not there to "evaluate" the president but to occasionally render reports to rooms of people where the president attends and listens. There is no testing nor evaluation in these meetings upon which the FBI could base such an evaluative case, nor is that really his job or place. There are many others who are around POTUS far more often whom you'd expect to notice a decline that could have and maybe should have noted and reported problems, but that is not the nature of the beast in Washington.
That Biden is paddling with half an oar now is apparent, but trying to blame Wray here I think is a pointless fishing expedition.