LrC 16.0: Presets don't apply their profile after cold launch

Since updating to Lightroom Classic 16.0, Develop presets that include a profile (Treatment & Profile checked) intermittently fail to apply their profile. The issue did not occur in 15.x.

Steps to reproduce

1. Restart the computer.
2. Launch Lightroom Classic 16.0 and open a raw photo in Develop.
3. Apply a Develop preset that includes a custom profile (XMP creative profile or DCP camera profile).

Expected result
The preset applies its profile.

Actual result
Nothing happens. The Profile field stays unchanged and the profile is not applied. Re-clicking the preset or waiting does not help.

The referenced profile is installed correctly: it is listed in the Profile Browser and can be applied manually from there without any problem. Only the preset fails to apply it.

Workaround
Quit and relaunch Lightroom Classic. After the relaunch, the same preset applies its profile correctly, even immediately after launch. The issue returns after the next computer restart.

Platforms
Reproduced on macOS and confirmed by a user on Windows.

Observation
The issue seems tied to the first launch after a system boot. It looks as if, on a cold launch, the preset’s profile reference is resolved before the profile index is complete, and that failed lookup is kept for the rest of the session. This is a guess based on the behavior described above.