Huge PL spikes without any conventional explanation

As the title says and since the latest update “Spearhead” dropped, I’ve been experiencing a noticeable increase in sudden PL spikes up to delirious 75% or even 93% lasting over fifteen to twenty seconds, some even kicking me from lobbies because of it. I already ruled out conventional reasons such as ISP performance or client desync.
Any educated guess what could it be?
Is it the servers with some ISPs? Could it be port-related?
Has it happened to you?