I'd say this is a pretty unique case where "both sides" doesn't make sense.
Typically, a surface trim operation, whether revolved, extruded, by another surface or plane or by a curve on the surface, reduces the size and changes the shape of the quilt. One side of the trimming object is removed, the other remains. When "both sides" is selected, the quilt is trimmed back and the part trimmed away is left as a new quilt.
In this case, the quilt is not really trimmed. It remains the same size and shape but is broken, or at least I think that's what you're after. "Both sides" here doesn't make a lot of sense because each side is the same quilt because it wraps around and meets the other side. Frankly, a "one sided" trim doesn't make sense either here because both "sides" are still the same quilt.
This really calls for a third option, perhaps called "slice" where the entire quilt remains but has a zero thickness cut in it like, as someone said, a sheetmetal rip.
That's why I said Creo really shouldn't do anything here, the traditional idea of a trim doesn't really make sense.