Coinbase Pro has gradually grown to lead the price action at times. That's going to put a strain on any company's operations. Bitfinex has been the leader in the past and they had the same crapping out in intense moments too.
An exchange going down at peak moments loses them plenty of money in fees. I can't see them doing it on purpose and there have been more lucrative and pivotal times to do it on purpose if that was some sort of policy.
Well, they might be losing money in fees but if they are involved in some sort of scheme to buy/sell before anyone else, I'm sure they would make a lot more money. If it's not on purpose, then it's a shit exchange that hasn't been able to solve this issue in 3+ years.