Thus far my changes to xdfs that were sourced from here and around the web have been increasing stability within other aspects of the program, like actual tuning of maps, being ablt to compare bins and so on.
I couldnt even open certain maps/scalars before without it crashing because xdfs were bad or setup wrong. Not the m-box stuff, just more obscure stuff.
What i have done is take known good working chunks from something like your m-box xdf and substituted it in for the problematic chunks that i find by hand. Then just change the location to what it was originally and it seems to fix it.
I must thank you for having a good xdf to be able to see what things should be formatted like.