Virtual crossing realization for maximally virtualized isotopy sequences

Let a virtual isotopy sequence be a sequence of diagrams and moves involving classical and virtual crossings. Call it maximally virtualized if it contains no sequentially virtualizable classical crossings, and say that it has switch-free ends if every sequentially switchable set of crossings is virtualizable. The initial and final diagrams are switch-free classical diagrams when they are classical and have this switch-free property.

Virtual crossing realization conjecture. Every maximally virtualized virtual isotopy sequence with switch-free classical initial and final diagrams admits a valid virtual crossing realization.

This conjecture concerns when virtual crossings in an isotopy sequence can be replaced by classical crossings to obtain a valid realization. The supplied text does not state whether the conjecture has been proved or disproved.