Battery sag under load variance

[Popeye]

Hey all.

It's an odd one. my mod is set to display pack voltage, and under load the voltage drop is not always constant.

I don't mean as the battery discharges because that is to be expected, I mean i can take it off charge and its different to the previous charge (both tests at fully charged)

For instance, when i take it off charge the battery sag can be 0.2V on the mods pack voltage reading, but the next time it can be as high as 0.6V.

Each time if i plug it in to Escribe and do a hard and soft reset and the sag returns to 0.2V without fail.

What could be causing it to happen?

I realise that 0.2V is a tiny amount, and 0.6V isn't a great deal either, the reason I am a little concerned is the fact that the sag can be 3x as much after just charging it up.

This is all running the same RDA, build, and at the same power setting