@Nevadacool well from what I see yesterday you have 12 subs which are a little above your average over the past 30 days and then all of the sudden you have 151 subs "in one day" today and the stats is falling currently at 63 and by tomorrow it will probably be back to your average around 10-15 a day. To Google's algorithm, this is a red flag because it's going to ask itself what happen? Then it's going to start watching those subscriptions. Do they engage with your videos, comment, or even watch your videos at all. You have to admit if you have 151 subs in one day and for the next 90 days NOT ONE of those subs clicked on a single video of your or watch more than 1 hour of video over those 90 days that's pretty odd. It's going to know you did "something" for those 151 subs because it wasn't normal and your stats show that. The algorithm doesn't know exactly what but it knows something is up because that's not normal.
And since YouTube knows ALL stats of EVERY single channel on the platform it doesn't have to guess what viewers normally do, or how true channel subs actually act when they sub a channel. How many hours over a month, 3 months, 6 months they watch video's from that channel and much much more stats that paint a picture, and a profile, of subs vs non-subs, etc.
Just tell you from my point of view because even though I don't have the experience that Google's algorithm does I am an internet marketing consultant and I have done my fair share of channel audits for both people and companies and have seen plenty of numbers from small channels to large ones. So even I know when something doesn't look like normal activity. It showing actions that do not fit the day-to-day activity that the channel normally has. So personally, however that 151 views "IN ONE DAY" happen, if it was my channel I can't say I would be very happy with how it happens because it's not going to do me much good. Actually, it's going to be more harmful than good in the long run.
Just in my opinion, you can take it for what it's worth.