I've linked to the upstream systemd bug report, although from comment #4 it sounds like it might be a regression caused by a security fix.
As to the dnsmasq patch mentioned in the issue description, what it appears to be doing is checking if there is a pseudoheader in the request, and if so adds the edns data structure to the response. I can't speak to what potential regressions might be concerns here, but the patch itself looks sensible to me. So, given adequate testing, I don't see a reason against considering SRU for this.
I've linked to the upstream systemd bug report, although from comment #4 it sounds like it might be a regression caused by a security fix.
As to the dnsmasq patch mentioned in the issue description, what it appears to be doing is checking if there is a pseudoheader in the request, and if so adds the edns data structure to the response. I can't speak to what potential regressions might be concerns here, but the patch itself looks sensible to me. So, given adequate testing, I don't see a reason against considering SRU for this.