When doing it for my robot generator test experiments, Level 23 of Vignettes appeared to save properly with DLE-XP, with no subsequent problems.
However, Level 21 of The Enemy Within generated a small problem. The level was not corrupt; it would still load with both DLE and XL. However the cockpit on the screen looked very wrong after saving, as shown by the images I've attached (named are self-descriptive).
Every other level of Enemy Within still rendered the cockpit correctly.
Thus I'm guessing this remnant bug may be a problem with saving custom cockpit data (since Enemy Within has a custom cockpit and Vignettes doesn't have one), though I'm by no means sure.