Version of vRA?
I had a similar problem -> vRA 7.4 + Custom Form -> Custom Properties Values not Updated in vRO Maybe this is also the case when requesting machines with the CloudClient? Can you check if the property option "Show in Request" is checked on the working properties and unchecked on the not working ones?
RobertDrink coffee.. Do stupid things faster with more energy...
Version of vRA is 7.3
I can take another look when I am back in the office after Labour Day -- no, that's not a spelling mistake. This is vRA 7.3 so I'm not sure if your idea applies here, but it's worth a shot.