Today I visited a PM, deleted it, silenced the user, then after navigating back (back button) through it I got an offline error. It persisted when I tried to continue going back to meta mainpage.
It looks like you are offline! Please check your network connection and try again.
I can duplicate the problem by visiting the topic normally then hitting Ctrl-R to reload:
The error page that I get is coming from Service Worker:
I’m on Chrome Version 63.0.3239.132 (Official Build) (64-bit)
This kind of smells like it’s related to https://meta.discourse.org/t/sorry-we-couldn-t-load-that-topic-possibly-due-to-a-connection-problem/40078/11?u=supermathie.