This also occurs in normal play without VR, using standard trackir. I'll work on getting a track and video of this happening.
Steps to reproduce:
Start up hind with friend in the PC seat, occupy CPG seat.
Activate weapon systems and start up missile guidance system
Open sight
Fire missile, optionally tracking to destroy target
Close sight
PC manoeuvres, egresses
Open sight
After one or several repetitions of steps 3 thru 6 the sight will now be canted to approximately 45 degrees and be pointed wildly off-axis
You can see this happening in this clip from a recent stream I did with a friend, my view is visible in the upper right corner. I have several tracks corresponding to this stream, since we discovered the issue could be temporarily resolved by restarting my DCS and re-entering the CPG seat, though I haven't included them here since they're fairly long. Our intention is to generate a fresh (short) track that demonstrates the issue as quickly as possible.
https://clips.twitch.tv/DullCheerfulWolverineDatSheffy-t4TSz8FRfY1bgg_w