missing timelines after user preferences change

Windows 10 v1709, Resolve Studio 15.1.

When user checks "Load all timelines when opening projects" and restarts Resolve, timelines previously not loaded are missing from the bins and from the "Select Timeline" dropdown list.

Repro:

1. Restore a PostgreSQL 9.2 DB dump (Resolve 12.5) into PostgreSQL 9.5 using Project Server
2. Upgrade restored DB, optimize, connect DB in Resolve's Project Manager
3. Load a project into 15.1, the default state of "Load all timelines when opening projects" is off
4. Load several timelines out of maybe twenty-thirty timelines available in the project
5. Under user preferences enable "Load all timelines when opening projects"
6. Restart Resolve and load the project again
7. All timelines not loaded in step 4. are missing from the bins and the "Select Timeline" dropdown list

I tried the steps two times and got consistent outcome. Note that even with "Load all timelines when opening projects" checked, a very complex project that takes over six minutes to load on V12.5 took just twenty seconds to load in V15.1, likely indicating that all timelines are either not loaded into RAM or that they are truly purged from the DB during an earlier step.

If you still have 12.5 running somewhere, what happens if you manually export that DRP, then take the DRP and put it on the system running 15.1 and import and update the DRP? Do the timelines then come up correctly?

I had a situation recently where a client I had back in April came back with some fixes in September, and luckily for all of us, I still had all the (converted) sessions in the Project Manager. Much to my shock, though, the Camera Raw settings did not get converted correctly and were at a default in the (converted) Resolve 15 project. I solved it by rebooting into 14, grabbing all the stills for every shot, exporting the DRP with stills, then manually bringing that back into Resolve 15.1... and this time, all the Camera Raw settings were intact and everything was exactly as it should be. (Frustratingly, some timelines had the Camera Raw settings and some did not on the old imported session. New imported session was flawless.)

I'm befuddled as to why it happened, but it does show that moving sessions across a radical version change can be dicey. And that goes for any software, going back decades. Sometimes you lose a little in translation.

I'll try the DRP trip. The issue may not be related to the fact I restored an older version database. But I ncluded those steps just in case.