Why does Sticky Multiple Account Info issue 2 reports if a new pair of multiple accounts has been found?

This software does not think in "pairs" but in "groups" or "sets" of accounts. There can be more than 2 accounts using the same computer. It issues a one-time report for each user account it detects. You won't get another report for any user a second time. If 2 new accounts are found to use the same computer a report for each of those 2 accounts will be issued consequently. If at any time in the future a third account will be found sharing the same computer just this third account will be reported. If you don't like this, you can activate the "Send 1 Notification per Detection Only" switch in the options of this add-on.