We just got back from a 6 day trip - and had the exact same issues with our bands. I brought 3 older ones from home and declined all the gray sets they offered us at check-in since we have so many already.
All FP"s worked great the entire trip on all bands.
But my band kept failing at every park gate (thankfully I had my AP on me)
My son's band worked great for 2 days and then failed at the gates on the 3rd and last day. (thankfully he had his 4 day
DVC promo pass on him)
On our 4th day a cm at EPCOT's main entrance gates asked to look at them, stating she had seen this problem before and suspected the bands were somehow cancelled in the system. Using a service station set up right at the entrance she went in and immediately reactivated them. No visit to Guest Services Required!!
and both mine and my son's bands kept failing to let us into our rooms at the VGF - which after wasting over an HOUR at VGF to try to check in - They finally just let us into the room manually and continued working on our bands for another 1/2 hr later that night.
I kept asking for a plastic key but that seemed to fall on deaf ears as they gave no reply and just kept busily working with tech support, cancelling and rebooking our reservation and rescanning the bands over and over again. they'd no sooner get 1 to work - the other one wouldn't and vice versa.
Then we'd try them at the doors and we couldn't get in. Fortunately we only had a short walk back and forth during this process. I can't even imagine being at SSR or OKW
I knew this had nothing to do with the cm's so I just patiently sat there but we wound up rushing to AK that afternoon to use a few FP's.
My husband's band had no problems the entire trip.
Our problems continued when we switched resorts to the AKV concierge. My son's band worked the room but not the concierge elevator or the dining plan / my band worked only for the dining plan and nothing else and my husbands worked great. I just told concierge to forget about trying to fix it at this point but she still kept wrestling with the system for close to an hr. after I repeatedly asked to let it go!
It's too much of a waste of time at check-in!
I lost over an hour at VGF and close to another hr. at AKV because they keep trying to work on these bands even after you insist they drop it. I would have lost even more time at the gates had I not had my AP.
Thankfully the FP's worked for us as well or I can't imagine the amount of time that would consume.