Spontaneous Uncoupling other than Sherman Hill

I've started to have uncoupling issues like Sherman Hill stock, except it's on my Donner Redo route. At least that's the only place I'm experiencing it right now.
It happened between a Donner Pass tank car and a reskin of Mainlines new box car. It's Mike's CN reskin. I don't know if that has anything to do with it or not.
It happened between a Donner Pass tank car and a reskin of Mainlines new box car. It's Mike's CN reskin. I don't know if that has anything to do with it or not.