The bend radius of a cable is all but universally at least 5-10 times the width of a cable. It's pretty safe to say that a bend radius of one, like this enclosure has, is out of spec.
Considering the cables are made by the same company as the box itself (WDLabs) and that we've sold almost 1000 boxes and haven't had a single person tell us the cables were problematic and considering I've personally put together a dozen boxes and taken them apart and together again many times and still encountered no issues I think I can safely say: it is just fine.