This does look suspicious. That is a lot of bot accounts... kinda looks like you bought subs or someone spam-purchased subs for your account. See how rhythmic the cycle is? You gain 150 then immediately lose 160, gain 80 lose 70. There is a net gain of 9 subs over the course of the month, which means that it was an almost 1 to 1 ratio of subs to account deletions.
Just looking at your Socialblade screenshot with no further information I am about 85% confident that this was purchased subs and almost 100% sure that these are bot accounts.