Balance issues

[G-UNIT]

I have 2 2s 5000mah flightmax batterys that are giving me some problems.
Charging them is no problem, weather I fast charge at 6amps or slow charge at 2.0
amps , but when it comes to balencing them I get a read out that I have an open balencer port or low or high balance voltage.
then after a day or so I charge again and the everything is fine, they charge and balance with no issues, then it starts again at another time.
Whats going on, are the batterys going south on me? they are about year old with god only knows how many runs on them maybe 15-20.
Any help or suggestions would be great.

[G-UNIT]

Any body?

[jcald2000]

Check the balance wires at cells plug with a volt meter while wiggling the wires.

[JimClark]

check the voltages of each cell. What charger are you using

[G-UNIT]

hyperion, for got the model but it's ac/dc charges single batterys.
it's a good charger never gave me any problems.