Load balancer error 502

[pmadr]

Hello,

Today morning approx. at 6 am UTC the Global External Application Load Balance started to give error response 502 each approx. 5 minutes. Other requests are successful. It had worked fine, we did not any change in the config.

What can be the reason?
There is a status detail: "config_not_found", in he request payload, section cache Decision 

I'll be glad for any help.

[pmadr]

Strange, it stopped to send 502 errors at approx. 6 PM UTC without any action from our side. Google platform did not report any issues today although it probably changed something. We are paying a lot of money for GCE so we would deserve some explanation. It seems not very reliable that sometimes it works and sometimes it doesn't work without any info.

[ventsislavg]

We also sporadically get the same config_not_found error failing single request one/two weeks apart. We haven't made any modifications to the LB or backends in those time frames.