Right now we're experiencing an issue where a small percentage of end users on our GKE site are getting super slow speeds. The issue is ISP related as they can switch to a 4G hot spot in the same location and get normal speeds... and inside our system the timing looks normal. So there's a slowdown either TO the load balancer or FROM the load balancer. Took a week to convince Google's support contractor to even believe it wasn't an issue with our site and their advice is generally along the lines of Turn it off and Turn it back on again (which might actually fix the problem) though that's easier said than done in GCP.