Possible Lipo problem?

I have a Premium Power 4700 20C 7.4v lipo. Ive noticed in the past couple of months, it reaches cut-off, 6v, too soon i believe. When i chuck it on the charger & check its voltage, its not even under 7v, 7.5v is the lowest ive seen it. Im using a mm with vortex 7.5 motor, fan on both motor & esc, TT01 geared mid 7 fdr

I believe under load, its hitting cut-off, voltage spike, or amp rating of pack is not strong enough? Ive also noticed lately the pack is coming off from a run warmer & warmer. I thought it might have been the plugs so i changed them to TRX but problem/issue still persists. Im thinking of buying a higher C rated, higher capacity pack, If you guys know what the problem might be, any info would be great