Do your self a favor and only use 2 of your 4 chargers from now on:
TIMER CHARGERS SHOULD BE BANNED!
Secondly your running stick packs(Unmathced cells) And there is no way to properly discharge individual cells on a tray in order to then DEAD SHORT. Dead shorting should only be done with proper instructions and equipment. Also you will loose run time when dead shorting.
Sounds like your sport type packs are the problem. I would recommend you try a low end mathced pack that u assemble your self. Cells are matched and will charge and discharge equally. Sounds as though your 3600 has a bad cell or a poor tack weld.
Do me a favour and try your 3600 one more time using the following steps:
-Using your ICE charger
-set it for 6amp charge
-delta peak of 5mv per cell 30mv
-First discharge the pack 10-30amps
-set charger to lock out mode(ice should do this other wise your lrp should)
If it still dont charge then set up the LRP or ICE to do 3 cycles. If this dont wake the pack up there is very likely a problem with a cell.
I have never had issue like yours with any batteries i have used 2400,3000,3300 ect. But i always run mathced packs (SMC RACING).