Using Old FDFL (Free Data For Life) SIM to Satisfy 40-day Unlock Requirement

I've got a couple free phones with EIP's on them that I'm not currently using. I had a still-active FDFL SIM from 2019 in a drawer, so, just as an experiment, I popped it in one of the phones. (For those that might not remember, a FDFL line gives the customer 200mb every 30 days. It's data only... no voice/text, but DOES have a number attached to it.)

After 40 days, looking under the unlock section, I noticed the red checkmark for the 40 days needed was gone. Actually, that entire sentence was now missing & only the checkmark for "Must be paid off" was still present.

Phone will be paid off in 2 months.... I'll update here if it works, but if it does & you're still holding onto an active FDFL SIM, this might be a great way to get those T-Mobile phones unlocked.