It's a sad day... Affinity Photo and Designer ver 2.0 was released, and unfortunately will no longer work with CTA5 (nor 4 I would assume).  The new version of Affinity applications install into C:\Program Files\WindowsApp which Microsoft, for whatever reason has made it inaccessible.  Tis true, Microsoft has hidden away folders and files on your very own system, and you cannot access them without some kind of registry hack.  Supposedly there are alias files for these hidden locations, but unfortunately, CTA5 will not accept them.
So, if you're an Affinity user and use Photo or Designer in CTA5, either hold off on upgrading to version 2.0, or don't replace your older Affinity apps when installing the new ones.
Either way, I'm really kinda miffed about it.