There is another post regarding this error occurring in Final Fantasy XV and I'm having this issue only in Fallout 4. I think that it has to do with update 4.06. Other posters also say to make sure you don't use Quick Save too frequently and to create manual saves. A complete reset and reinstall of the PS4 seems to have helped with this for one user, but it hasn't helped for me.
Options you can try are to uninstall and then reinstall the game itself. Turn on the PS4 in Safe Mode and choose the option to Rebuild Database. Last resort is a complete wipe and initialise (the final complete reset of the system to ensure the patch is reinstalled).
Hope something here helps.
