It will crash later if that's the case; the old ii_maximus_arm variant won't work with the updated maximus hull. There's a reason it's deleted.
The problem is you have some other mod that apparently references the ii_maximus_arm variant. I have no idea what that mod may be, since it's not any of the ones I have in my mods folder - a grep for "ii_maximus_arm" turns up absolutely nothing in all of my mods, including II 1.12.0. To find which mod is doing it, I suggest getting Cygwin (if you're on Windows), cd to your mods directory, and use the command
It will print out anything that has the phrase "ii_maximus_arm".