I'm thinking that there might have been an update to the search results and/or videos that appear in the suggested vids list. Not a change in the algorithm as such, but an update of what videos get promoted by that algorithm if you see what I mean.
I say that because myself and
@babyteeth4 are both seeing the opposite - approximately a sudden 35% increase in daily views from the exact same date onwards. I've had a look at other channels' stats on Socilablade and a lot of channels are seeing either a significant increase or decrease in views from that date. Just a theory, but it seems to happen every 6-8 weeks or so in my experience.