Lights Blinking on Battery Charger

I posted this on the Unofficial Tech Support site - but decided to move it here:

Over the season, I’ve had quite a few rechargeable AAA batteries cause the red led on the charger to flash. I have assumed that this means that the battery is no longer any good. Is the true?

If so, it looks like the mortality rate for those batteries is really high. In that case, what do most teams do - just use Duracell?

It appears that the flashing lights mean the battery is bad. If this is the case, I’ve had numerous batteries go bad way too fast. Could this mean that the charger is defective? I could have much more economy of scale just using Duracell batteries.