Sorry, not exactly sure where to ask this, but we have a drawing of a boat and it has bulkheads in it that look like this:

And when we do certain things (for instance, if we draw a shape and try to extrude it), all the bulkheads turn to this:

This even happens if the sketched part is not touching/merging with any other part on the boat.  This was also happening the other day when I would measure a bulkhead and then go to measure the next bulkhead everything would convert to these squares/rectangles.  There are also no notifications when this happens, it just happens, and there is no undo option for it.

Is there a reason why this is happening or something we should be doing differently?  Or there a way to revert them back to their 'bulkhead' shape?

Thanks in advance!

EDIT: Sorry, I guess there are errors to do with surfacing/sketches.  File is attached.