I've previously attempted to report this bug before, however i've since gathered some information about it. From what i could experience, entering the SOI of certain planets will make engines behave strange. Engines will be unable to move the orbital trajectory of the craft normally; instead, only the "upper" hemisphere, relative to either the planet or camera, completely randomly, will fire, and sometimes all or none will work depending on craft orientation.
In map view, the craft is displayed as having a near circular orbit around the outer edge of the SOI boundary.
Attempting to time warp will not work correctly either, instead it will display any random velocity (usually 1 digit, but in most cases just 0 m/s). In map view, time warping will sort of just break the orbit, the craft usually goes off of the displayed orbital course, spinning in circles around a random point, with a "leash"-like orbit line attached to a fixed point on the displayed course.
From what i've seen and tested, this happens with 3 of my planets, those being Mraz from Mortan 1.2 (shown here), the "???" joke planet from Pazfigust (this is the reason why i didn't include it there), and Dolorterrore from Havron (same reason as in Pazfigust).
In the sandbox, the craft is aligned and heading towards Mraz, with it entering the SOI shortly. I have included a spawn location at this spot, just in case it's needed (i believe it's named "bug reproduce attempt spot" or something like that).
It is unknown if this is device-specific, but most likely not craft-specific as i have tested and successfully managed to get this bug with both the SV80 (seen here) and the Comet Head, both being my current 2 interplanetary and interstellar crafts.
Dev Notes: There are some errors in the log related to building orbit line meshes.