changing out bod members is actually fairly standard when it comes to uplisting
It is?? And what uplisting? They say nothing about any actual plans to uplist in their S-1.
This is exactly what happened in 2011: the U.S. directors jumped ship. It wasn't a good sign then, and isn't a good sign now. It will also cause problems with getting the S-1 declared effective.
Of course the resignation may be the result of problems with the S-1.