We're told to expect changes, so we notice declines that 2 months ago might not have stood out. If there is a slight increase in volatility from the update, it will appear exaggerated because every change will be atrributed to the update even if 80% of them would have occurred before. Could be Training, could be Coaching, could be the Update. The Update is new, so that's going to be the assumed cause. It could be in this case, but it's not as though a 28-yo declining never happened before. Without taking the time to analyze it statistically over a large sample size, there's no way to know how many spikes are from the update vs. same old, same old.
The player in question has low Health/Patience and high Temper, all of which make his development more volatile with or without the update. But with rounded numbers, 1 point is insignificant (could have been 84.504 to 84.493).