Piwik tracking working on 1 of 2 sites... not the domain it's installed on

Hi. Piwik (latest version, updated today) is tracking two WordPress sites. It’s installed on a subdomain of what I’ll call the primary site (ExpectPerfection.com), or “Site A.”

Strangely, stats are showing for Site B (ExcellentPresence.com) in BOTH Site A’s and Site B’s Piwik dashboards and WP. (WP-Piwik had swapped the two site IDs when using auto-config. A few days ago I realized and fixed that.) Now, Site B’s stats are tracking flawlessly, but Site A’s stats are NO LONGER tracking anything.

I tried duplicating the settings from Site B’s WordPress Piwik to Site A’s WordPress Piwik, as well as deleting/reinstalling Site A’s WordPress Piwik. Nothing has worked.

This is so strange to me, since Site A is the very domain with the stats package installed on it! I didn’t see an issue exactly like this. Can someone help, please?

Q1: Is there a low-tech, easy way to get Site B’s stats out of Site A’s dashboard reports? (Inexperienced with MySQL.)

Q2: Why isn’t Site A being tracked now?

Thank you!

-H.T.

P.S. I saw “PHP Warning: Unexpected character in input: ‘’ (ASCII=92) state=1” in the error log of the subdomain installation. My PHP version is 5.4.43—higher than 5.3.3 as stated in the help doc here—so I just deleted the related cron job. I had switched to autoarchiving anyway.