PlusKit allows you to combine anything, however not everything that it lets you do is something that you should do.
PlusKit is a pro level tool -- as such it does not provide warning-stickers or guard rails. It allows you to give it a try and see if it works. In this case the answer is certainly: no it does not work. As a pro-level tool it is up to the user to notice this, change course, and move on.
PlusKit has allowed you to combine things that should not be combined. It's like adding a Jet Engine into a VW Beetle -- there is no "fix" to make that work -- it simply will not.
The best way to move forward from a broken @import is to take a step back and try a different solution to solving the problem at hand.