Ok all, have a 1 cycled GensAce 25C 4s 5300 lipo....one cell appears to be dead after one charge...

I am using a hyperion charger 615i duo 3. How can I try to recover that one cell? IT's not the balance board as I am charging a 5s as we speak. Tried changing boards with the same results.
1. MBX-6 T8 1900KV, RX8 ON 4S
2. MBX-5T 1520, MMM ON 5S
3. MBX-5 ONROAD CONVERSION 1515, MMM ON 5S
4. MRX-3 ON ROAD CONVERSION 1512, MMM ON 6S
5. TEN T 2650 T8, MMP ON 3S