What does "a lot of flame movement in second chamber" mean as related to a furnace heater and what are its implications?

It means that cell (#2) has a possible crack in it and could be allowing carbon monoxide to enter the living area.. Was this diagnosed by a HVAC Tech? Best to have a carbon monoxide check done using the proper detection equipment. Could be other possibilities, but best to rule this one out

Yup have it looked at, not worth messing with a possible crack.

Yes, it was looked at by a HVAC maintenance technician.

And, he said??

He said that the inducer motor is drawing high amps and there is a lot of flame movement in the second chamber.