Yes, that is documented here, including workarounds to alleviate the issue: [Bug] /usr/libexec/sailfish-osupdateservice osupdate-check sets ssu re
No, IIRC that does not work. IMO it takes one of the workarounds described in aforementioned bug report (rsp. its follow-up posts) to alleviate the bad side-effects of the misbehaving systemd user unit osupdate-check.service.