I am even more perplexed.
After your further report and that of aWac9 I promised myself to stress the Sphere in every way to be able to recreate the reported error.
Today I had some time again and, as much as I tried everything that came to my mind, I was unable to get the error.
I also installed, in a complete way, all your simulation of Abrams (I had not done it yet because I was more interested in the bike and peek in the script) thinking that with the queries to the plugin and the creation and destruction of the "evaporable" models I would have better conformed to your configuration ...
Nothing to do ... the Sphere flies as usual.
Just an attempt ... if you feel like ...
Try to transform lines 1244 and 1245 into comments, they are used to remove sensitivity to vibrations when piloting "in first person". This is the only slightly exotic command that I can think of having used and could be interpreted by Outerra as a forcing ...
I believe very little, but ... when you do not find obvious causes, proceed by trial and error ...