Heat Pumps and Electric Heating - Fan Motor bumps on shutoff

Although I have a broad base in electricity, heating and cooling ain't my thing so I am looking for someone more knowledgable. I have a Goodman furnace model A30-15 and a Goodman heat pump. The furnace is about 15 years old and I replaced the fan about 2 years ago, this problem started about 6 months ago. When the blower shuts off I get a bump that sounds like the duct rattles but it's inside of the unit. What is strange it this only happens when the fan is shut down by the unit. After a heating or cooling cycle the compressor shuts down like normal then after the timing cycle the fan makes this loud bump noise. What I did was set the thermostat to fan only and it came on, I turned the thermostat back to off and when the fan shut down I heard the same bump. I turned the thermostat back to fan only and after the fan came on I shut the fan off by the circuit breaker and it shut off fine with no bump noise, tried it a few more times and it was fine so it appears that this only happens when the fan shuts off by the timer function. Looking at the wiring diagram it appears that the fan is controlled by the Blower time delay relay. Could this relay be bouncing internally (turning off and then bouncing back on and then off) causing the blower to jerk? Does this relay supply the timing function or does something else supply the timing function to control the BTDR relay? It appears all the connections are tight and I can't see any reason for this. If anyone has heard of this before and can give me a little guidance I would greatly appreciate it. This is one annoying problem. By the way - can anyone recommend a good programmable thermostat for this unit?

it appears that the fan is controlled by the Blower time delay relay. Could this relay be bouncing internally (turning off and then bouncing back on and then off) causing the blower to jerk? Does this relay supply the timing
Not sure what blower control you have there . But yes on a fan control when its a time on or a time off they work like with a heater strip in them. So it can like go off but right back on. Have youchecked all wires ???? what I dont get it should be the same with on and off from the breaker. Do you let it run long there????

All wires are in good shape and the connections are tight and the motor only bumps when it turns off after the time delay. When the fan turns on it is fine. I can turn the thermostat to fan only and let it run for 5 minutes then turn it off from the circuit breaker and it shuts down fine - nice and quiet. Looking at the wiring diagram the only thing between the breaker and the fan is the BTDR relay and I am assuming that if it shuts off fine with the breaker but bumps otherwise it is either something with the BTDR relay or whatever is controlling the relay. Does the BTDR have the time delay built in or is it controlled by another timer somewhere?

Some time delays are from the boards and others or from just the fan relay. I cant say for sure on that goodman.I try and stay as far away from them as I can.