PMDG 737-800 on MSFS2020

I am doing everything by the book and aircraft is stable at VRef + wind correction at 1000feet, and ILS and MCP are correctly set up, but as soon as AP and auto throttle are turned off at 1000 feet, aircraft quickly becomes unstable and unable to land correctly. Is this an issue that others have also encountered?

I have been flying and landing the Fenix airbus A320 with no issues, and have also been able to land the LEVEL-D 767 in FSX in the past with no issues.

Any tips are appreciated, I just want to know what I might be doing wrong.

We need more information about what exactly is meant by "as soon as AP and auto throttle are turned off; aircraft quickly becomes unstable and unable to land correctly." Based on your statement, the airplane is stabilized, and after the disconnect, it should continue to fly with little to no corrections. Is the airplane pitching up or down, or are there any uncommanded power changes? One issue may be instability after the A/T disconnect, caused by a sudden power change to idle. Before disconnecting the A/T, please manually match N1/EPR to avoid a speed change that could result in a pitch condition. I don't know; I'm speculating based on limited information. 

As you pointed out, the issue might be matching N1 prior to A/T disconnect, I checked and find it suspicious that there is no indication on the NI gauge to allow matching N1. The best I could do was mentally note the N1 and attempt to match it quickly.  BTW the instability exhibits as both a pitch change and heading deflection.

 

46 minutes ago, mali6491 said:

As you pointed out, the issue might be matching N1 prior to A/T disconnect, I checked and find it suspicious that there is no indication on the NI gauge to allow matching N1. The best I could do was mentally note the N1 and attempt to match it quickly.  BTW the instability exhibits as both a pitch change and heading deflection.

 

What kind of throttle controller do you have? It might be related to that. If you have a rollback on one engine (thrust doesn't match) after A/T disconnect, it will yaw, and as it loses speed, it will lower the nose and destabilize. 

7 hours ago, mali6491 said:

As you pointed out, the issue might be matching N1 prior to A/T disconnect, I checked and find it suspicious that there is no indication on the NI gauge to allow matching N1. The best I could do was mentally note the N1 and attempt to match it quickly.  BTW the instability exhibits as both a pitch change and heading deflection.

 

You can select the N1 reference option in the FMC PMDG Setup

I will pay attention to that. I have only a simple Logitech throttle since I had to return back my Honeycomb Bravo.