Certain apps fail to update from Play, while others work

Certain apps fail to update from Play, while others work

I have been having this issue between ROMs, as well as between
connections. I am currently running ParanoidAndroid 3.94 (Android 4.3)
with franco.kernel 3.0.89. The apps that consistently fail for me are
currently the following:
Minimal UI Go Apex Nova
SwiftKey Keyboard
TuneIn Radio Pro
Endomondo Sports Tracker PRO
Other apps consistently update fine (example: Facebook). The error I get is
Update for "application-name" could not be downloaded due to an error. (403)
I have eliminated the following factors:
Network issues (issue persists with two separate Wi-Fi points, as well as
mobile data)
Google Play cache issues (I have cleared cache and restarted the Play app)
What makes me suspicious is that all of the 4 apps listed above are apps
that I paid for in the past. Experimenting with this has indicated that it
might be an issue related to my Google Accounts (I use two Google Accounts
in parallel, one "regular" gmail account and one with Google Apps).
If I "sacrifice" one of the apps that do not work and uninstall "TuneIn
Radio Pro" from Play store — I am then also locked out of actually getting
the app back on my phone. The button in the Play store says "Install"
(note: not "Purchase", so my existing ownership is recognized), I click it
and "Accept", and the app even starts downloading! However, after the
installation starts, I get the following error message:
Error: Package file is invalid
So now I am effectively locked out of getting an app that I paid for.
Now, I am able to get all of these apps just fine on another device I have
(Nexus 7), so I appreciate the fact that there is something up with my
phone that causes this. However, I am not certain that it has to be
something with the phone as it can also be something on Google's end not
handling my dual accounts very well and therefore throwing the 403
(Forbidden) error when I try to download an app I actually own.
Any ideas on what to do to troubleshoot and/or solve this would be greatly
appreciated.