Trouble with Austroflamm integra

Just got the stove (vintage model V1) The stove turns on as it should, but what happens is that after startup, and the stove is firing nicely, the distribution blower comes on as it should, and feeding at a very high level, I can turn the dial back, and it seems as though the stove does not respond to my input of lower feed request. Then out of no where, the stove acts like it is in shutdown mode (sort of), except the room blower continues, and the feed motor only feeds enough to have a few pellets continue to have fire or embers in the burnpot (like its on thermostat, but its not on thermostat. Light only blips fraction of a second), then after a few minutes, the stove returns to feeding normal with the feed light on for a few seconds off for a second or two then on again, and the fire builds up for about 3-5 minutes, then it goes back to auger minimum and the fire dies down to embers again (all without any change on user board setting). Then once in a while, when things are going well with a big fire, the exhaust fan cuts back and I get a lazy fire and pellet start stacking up. The stove has a new exhaust fan, and I was told a new air card.

that would make perfect sense for a stove that was running correctly. Mine is doing all the right things at immediate startup, until it's not. Let me try to explain again. start up is reasonably ok. Air is being drawn into the stove, and the fire burns with yellow color flame for approx 6-8 minutes. I turn on the feeder at this point, and it feeds into burn pot without any adjustments that I can make. After about 5 minutes of constant feed, the auger motor abruptly shifts to minimum feed, in which I still have no input at the control knob. The fire dies down with briliant glowing flame, and then the burnpot is reduced to glowing embers, and the feeder drops a single pellet or two at each pulse of the auger for approximately 3-5 minutes. Then, the stove suddenly shifts to a new phase, where the comb fan slows, and the feed now picks up, and I get a slow orange flame, and the pellets build up, and at this point, I can adjust the knob, and here the convection fan speeds up or lowers, depending on my input, but the pellets are not changing drop speed, and I do not hear a speed increase or decrease in comb fan. The stove is clean in all areas, and I believe that the air card is new and exhaust fan is as well. The previous owner had sent the computer board to Joe Narduzzi (expert in Austroflamm?) to insure proper running condition, as well as the verifying the air card to be correct as well. I took the stove with the knowledge that it had a problem, but I cannot for the life of me figure out why its doing what it is doing.