Ok but did fixing the slug add the counter in that instance? Worked for me. You may need to impersonate a user to accumulate a count (not sure if it registers admin clicks? Might not. Hence you need user account to check?)
Is it possible no user has clicked those links where the slug was up-to-date in the link? Don’t think using admin account is valid check.
i also think accumulation presently isn’t supported for targets involving mid post headings.