Jon,
My point was RE the Apple case not being an issue. I too have some knowledge of the effects of ESD after working over 30 years in the IC industry, both analog and digital layout. By no means an expert in the ESD field though 😉
If I may? I believe this is the first time I read your mention of the 15 minute or more block failures. Is that repeatable? If so, you could open a case with Apple asking for backline or second tier or whatever they call it support. I've written this before here and apologize to all for the repeat. They have a "profile" they can E-mail to you which, once installed, collects extensive TID data logs which you then send back after the failure. If it's random I don't know how they handle that as the person I spoke with went into hand holding mode while I tried to duplicate the issue I had.
One final note: It's not just Twitter that causes temporary TID to fail. I'm sure you read that here and know about the Control Panel calculator hack to reset whatever goes brain-dead and TID loses focus. It sounds as if that's not the case, and others here have recently had the same TID goes out to lunch for an extended time. It should also be noted that apps don't have to be in the foreground, or background, to (perhaps) cause a problem. If notifications are on for apps configured to receive push notices, you could have activity you had not thought of which could be affecting TID.
Question: When you were in the 15 min TID lockout mode, did you by chance go into the TID enrollment screen to see if an enrolled finger highlighted?
Okay, a final, final thought 🙂 I've seen in other threads where TID was not even available, and was greyed out. In this thread the advise was related to an App Store reset. Not clear to me why TID wants to have a proper App Store entry. What if one doesn't intend to purchase apps, or haven't set an acct up yet. I bring this up only because, it sounds as if IOS, for whatever reason, tries to validate an App Store acct, and if it fails, TID is disabled?!? Dunno about that as I haven't experienced it. So, if that's true, and for some reason the App Store was not responsive, for whatever reason, I guess I could see cases where TID could be broken. Beyond my pay grade 🙂