Problems come up in QP recently where some form of network lag has made the game unplayable. I would characterize the problems started a couple of months ago, and with another uptick after patch 1.13.0.1.
I have a very stable gigabit ethernet connection, and repeated latency queries from online speed tests shows a consistent 1 to 2ms latency metric; I have observed this issue regardless of background network traffic on my computer, and have done speed tests during the problems that do not indicate anything obvious on my network.
In a problematic game, the problem typically arises part-way through the match; the bare-bones latency metric (reported alongside the FPS, GPU temperature, etc.) in a normal game ranges between 30 and 50ms (stable at a given value through the game), but changes sporadically in a problematic game between 30 and 80ms.
Looking at the network debug screen when this happens, the IP points to the 24.105.x.x block (Irvine). The yellow LAT line averages 1ms on a good game, but averages ~30ms on a problematic game. Additionally, the line is very erratic, and will periodically result in an orange highlighted bar, as per Blizzard Support - Diagnosing Overwatch Network Problems.
When asking the game chat when the problem occurs, I usually get one or two confirmations of similar issues from fellow players – I have not asked during normal games.
If I am in a group, I would ask my friends about this issue, and the person who lives in my city, but on a different ISP, would report similar issues (while others living in another part of the country do not report this issue).
In order to resolve the problem, I will exit to menu after the game, and wait a while before reconnecting. Checking the network graph, the server changed.
I should mention that my network configuration has not changed within the last year or so (i.e. it has remained the same both before and during this problem).
From all of this, it seems like there may be a server issue on Blizzard’s end; I’m not sure how else I can diagnose this problem, but I’d be happy to help.
EDIT: Sorry, read the forum guidelines – seems to be a dup of Wave Broadband California Packet Loss - Nov 22 2018 - #28 by Trifecta-11327.