This is evident in 11.2.1:
1. Create new session.
2. Create new mono audio track.
3. Create a send to a stereo bus on the audio track.
4. Enable "FMP" in the send window.
5. Disable automation (auto off).
6. Start transport.
Now turn the pan knob on the channel. When you release the mouse button, the pan knob in the send window returns to where it originally was. With the transport still running try to go from "auto off" to "auto read". Now the pan knob on the channel also returns to where it originally was.
In PT 10.3.9 it works as expected.