I had this happen. I flew it, cautiously at first, but after a few minutes of normal power consumption and steady flight I just ran with it. Next charge all LEDs worked. I dunno??? But it was one of my 48's (#3) so I'm glad there's now no signs of problems. I hope it goes the same for you.
I have had this happen on one of my TB48's but it only happened from new out of the box on its initial charge.
I kept a VERY close eye on this pack for quite a while but since this one and only occurrence (from new) I have over 25 flights on the pack with one deep discharge to calibrate and all cells track closely to each other and it has charged correctly (all LEDs) ever since. It has also had a firmware update in between with no problems.
I now trust this pack
Thanks for this thread. I was going to post a question, but this seems to answer it. One of my four TB47 packs charges to 100%, but rather than the lights all going out when fully charged, light 3 continues flashing on its own. If I disconnect from the charger and press the button, all four lights indicate full charge.
This is not quite the same as the OP issue, but I too will isolate and cautiously test this battery. It only happened after the most recent FW update by the way.