As an experiment, I visited
Prosoft/Drive Genius to see what cookies would be bestowed upon me, with
these results.
The top screenshot shows the 7 cookies that Prosoft placed, and the bottom one shows the 3 that reappeared 1 minute after the 7 were deleted and every minute thereafter when they were deleted (by my Cookie 1 minute timer)
Obviously there has to be some reason for our differing results.
On the premise that the cookie might have been blocked just double-checked to see what I might be running that might have made the difference. I am running Safari extensions Adguard and 1Blocker, using DNSCrypt, and have additional blocks set on OpenDNS. When I get time this afternoon, I will try disabling each of those to see if it makes a difference.
Are you using Safari? I forgot to check which of the four browsers I have installed had the Prosoft cookie. Cookie Stumbler checks all of them and I only loo0ed at the consolidated listing and not the individual browsers.