Is it just me or do fragment drops FEEL influenced by the time of day?

Not impossible, there is good logic behind this and really fits GGG way of doing things.

They did confess that corrupted areas spawn rate was decreased since they wanted focus to be on the masters expansion. Now apply this reasoning to drop rates as a function of players online which is dependent on the hour of the day, i.e., if they want the NUMBER of each item id that drops every hour to be constant they would simply let the game reduce the drop rates when alot of players are online and increase the drops when few players are online.

No its just you OP I've farmed over 20 full sac sets since the corrupted map patch and I didn't notice any difference with regards to what time of day it was.