Makita 18v Li-ion 18v charging lights

[langtounboy]

I've done all the google search for this light combination but so far there's been no hits.
Battery BL 1830 3AH.
When placed on the charger the flashing green momentarily changes to charging solid red.
It then changes back to the flashing green only. 'Power supply to charger.'
The battery has 18+v at the terminals; I recharged it using another battery & will run tools.
The other batteries I have charge using the same makita charger.
I'm thinking it's the battery circuit card at fault but if there are any experts who have advice, I'm all ears.

 

[Swwils]

Pcb has bricked itself, will do this after 3 charging attempts and cells not balanced.

 

[opps]

From

https://www.makitatools.com/service/faq

Flashing Green Light – Ready to charge
Solid red light – Charging (Battery is below 80% charge)
Solid red and green light – Charging (Battery is above 80% charge)
Solid green light - Charging complete
Flashing red light - Delay in charging (Battery is cooling or the battery is too cold to charge)
Flashing red and green light – Defective battery
Flashing yellow light - Cooling abnormality
Solid yellow light - Conditioning