I read on here that you should run 3.4 wait for amps to drop to near 0 then progress up to 3.5 then 3.65
If you enjoy watching paint dry and grass grow.
Maybe just wait until it transitions from CC to CV, then progress higher? (disconnect supply from battery when setting for next higher voltage.)
So just did some testing with my volt meter. At the connection on the PS (3.6V, 0A), at the end of the leads not connected to battery (3.6V, 0A), and at the connections with the leads connected to battery (3.3V, ~5A)
I'm surprised the voltage at the leads with them on the battery doesn't show 3.6V?
Is current limit set to 5A or to 10A?
If you disconnect leads from battery (or from supply) and short supply, it should show current limit.
Measure voltage across cells, and voltage across supply terminals.
Measure voltage drop from terminal of supply to terminal of cell.
You have both wires at one end of the batch of parallel cells. That will cause some voltage drop to the far end.
Could be improved (at least marginally) by connecting one wire to far end.
Of greater concern is contact resistance between busbars, and busbars to cell terminals.
Measure voltage between each busbar and the next.
If you can poke a probe in, measure voltage between busbar and cell terminal. At least the positive on one end seems accessible.
One guy parallel charged his cells, and once separated one of them settled lower. Charging it separately brought it up.
Contact resistance will matter more discharging the battery at 100A than charging each cell at 1.5A, but it can still affect results.
Waiting for a reasonably low tail current at 3.65V should help.