PS4 BUG: Downloading Heavensward Expansion from PSN Store destroys local installation

The following is always reproducible on a PS4.

Starting point: All FFXIV Apps and save data are deleted, the system is completely clean of any FFXIV-related content, newest PS4 system software 2.51.

1. Go to the PSN store
2. Redeem your 12-digit Code for Heavensward
3. Start downloading FFXIV (base game) and Heavensward expansion
4. Wait for both downloads to complete
5. Start FFXIV, log in, and wait for the content download to complete

At this point, the game either crashes, and the error described below appears, or the download succeeds, and you can play ONCE, however:

6. Log out of FFXIV (close the FFXIV application completely)
7. Start FFXIV and log in again.

What should happen:
Login and play as usual.

What actually happens:
- Checking FFXIV version -> [20458][24530][20457][404]
- Cannot login
- Cannot play
- Have to completely erase FFXIV from the console, reinstall from PSN store (WITHOUT Heavensward), login again, go through the whole download procedure again