Seems like you are still blaming the user for his “very slow internet”.
How do you know the user internet was slow? Couldn’t a race condition like this exist anyway with regular 2 fast internet connections competing for the same sessions?
Something doesn’t add up.
this is a completely reasonable and seemingly quite transparent explaination.
if you want a conspiracy, there are better places to look.
Instead of saying "race condition that appears on very slow internet connections", you might say "race condition caused by real-world network latencies that our in-office testing didn't reveal" or some shit.
Like it all sounds like a business decision (limiting 1 device to 1 sub) which is actually that was confirmed both by the actual tech limitation (logging out users from their other devices) and your own support.
Blaming the AI, then the user connection, and then some odd race conditions seem unnecessary. You can just say it was a bad business decision, roll it back, and go on with your day. Instead of treating multiple paying users badly.