I have this exactly bug. It's reproducible 100% - I built an outpost launcher yesterday and it crashes (well, hangs the thread on Linux/32bit) every time I separate or stage-separate the TR38D. I've created a gist paste with the following 3 parts: (1) KSP.log (nothing here, really) (2) VESSEL part from persistent.sfs, so people can reproduce. (3) a PATCH that I made to my persistent.sfs that changed the TR36D into a mini decoupler. https://gist.github.com/sofar/b40760dacbdfab58a4b5 AFTER I patched persistent.sfs to "transform" the decoupler into a mini decoupler, staging correctly separated my vehicle (of course it left some struts floating which is likely what was the issue here to begin with). In any case, modifying the decoupler type seems to help.
