Wordpress migration puzzler

Hi guys, Who out there is up for a puzzle? My client had 2 websites built (Wordpress + WooCommerce). They both use the same theme (The7), same products, etc... only real differences are theme colors/logo and pricing (retail site = purple theme; wholesale site = orange theme) The first website was completed, then copied to a different domain using the proper WP migration tools to change the site URL and site paths (retaining db serialization, etc). phpMyAdmin and grep were also used to identify any remaining bits to ensure nothing linked back to the first website. Everything looked great. The theme on the new wholesale site was lightly customized (different colors and logos), so that customers and staff can easily identify which site is retail and which site is wholesale. No biggie, right? Well, for some reason the new site is not retaining its configuration. For example, certain paths to images and links on the wholesale site keep reverting back to the retail website version. And the retail site keeps losing some its info too. For example, the orange logo reverts back to a purple logo, certain CSS tweaks disappear or revert back to a previous (non-customized) version, and a link to their login form reverts back to the retail site. Both sites have similar issues. And occasionally, the logo just vanishes (broken image link) or the path changes to a product image in the media library -- an image that was never used for their logo at all (never stored as a path in the DB). Also, when logging into one website, the other website will automatically log you out (and vice-versa). Based on my explanation, you would think that these 2 sites are installed on the same domain, sharing the same database, or cache or session or something -- but nope. The retail site has its own domain and is hosted on a cPanel server. The wholesale site is hosted under a different domain on a different platform in a different data center. (CentMinMod). Both sites use local MySQL databases (not remote). On a side note: the wholesale site was tested on EasyEngine and RunCloud for performance testing, but the problem persisted on those platforms as well. In other words, there's no logical reason for these 2 sites to be connected, but somehow they are linked together. How bizarre is that??? Please understand this clearly: The installations were created on separate domains and on separate servers. Caching is disabled. Cloudflare is disabled. Database serialization has been maintained at all times. There's no logical connection between the 2 websites. I need some help locating and eliminating these gremlins!