After Upgrading to 6.21.1 I had customers calling saying they had no internet. After doing tests found out DNS query was not working nslookup www.google.com would time out.

Confirmed, I am seeing this exact issue on mine as well. Upgraded a site from 6.11 to 6.21.1 and DNS queries work fine for a while, then start timing out.

We discovered this during a major network reorg and upgrade today. It's pretty bad and happening on an RB450G. We've upgraded to 6.22 (which mentions a DNS fix in the changelog). So far so good, but it's only been ~20 minutes so it could still recur.

Has anyone else found workarounds? Do you know if 6.22 fixes it? What about temporarily disabling the hotspot.

(whoops double post)

Disabling hotspot and reenabling it does fix the problem temporarily. I rolled back to 6.20 and didn't give 6.22 a shot yet since the changelog doesn't indicate specifically that this issue has been resolved.

6.22 seems to have fixed this.