No, I have made no changes to my location.
What started this was some lights failed to turn on as expected at sunset-90, and I assumed it was because the sunset time is wrong in the IDE (I haven’t found where to check it in the app).
However, I then realized that some other lights did turn on as expected at sunset-75. The difference being that I had reconfigured the Smart Lighting automation for the failing lights, from a fixed time (6pm) to a relative time, while the working lights were already configured for a relative time.
I’m pretty sure this is just the SmartLIghting app messing up the underlying data when I edited the existing automation (changing it from a fixed time of day to a time relative to sunset). I will have to delete those automations and re-create them (good thing I kept notes on what settings to use).
Thanks for the response.