Thanks for the update, Malachite.
Please note however that the “MailChimp For WooCommerce” plugin was not among the active plugins listed in my System Status Report because I had disabled it as soon as I discovered the issue (it was randomly removing my best customers from my marketing stream; wouldn’t you immediately shut it off as well?!).
As the original poster of this topic, it is indisputable that your plugin is the cause of this “behavior” for me. To suggest that your plugin would not cause this issue in my particular case is a lazy, spurious and condescending bit of reasoning. The similarly named plugin from Ibericode has never let me down, and given everything that you’ve heard it’s pathetic that you would still somehow try to shift the blame on it.
The similarly named “MailChimp For WordPress” plugin was active in my SSR because I had immediately reverted back to it (as it was my previous provider). Regardless, it was clear just by examining the dates that this issue only occurred when I switched exclusively to “MailChimp For WooCommerce”. It should be noted by you that a WooCommerce SSR is a static document that does not track behavior (such as plugin statuses and usage) over time.
By the way, I fully support the views presented by @aand on the mishandling of this issue (to those who may not know, he reported this issue MONTHS before I did). The financial blow on my eCommerce business by this plugin has been enormous. I’m not sure I can decide to trust it again.