Notable update re: the headline > EDIT: With further testing (report from u/DJB719), it appears that the one sample of failure from T-Mobile iPhone to T-Mobile

Notable update re: the headline > EDIT: With further testing (report from u/DJB719), it appears that the one sample of failure from T-Mobile iPhone to T-Mobile Android may be a fluke, meaning the only reproducible errors are from T-Mobile to Verizon. That suggests that this issue could be an error on Verizon's end performing inbound message filtering from the T-Mobile network. If further results point in that direction, it may be worth having one of the Verizon subscribers call to speak with their tech support, as well.