What happens if you force Lightroom to regenerate the previews it uses? Select the desired photo(s), then Library->Previews->Build 1:1 Previews
Well, that works fine, thanks so much for that suggestion. At import I don't build 1:1 previews for speed reasons. So with this information what do you think is going on and how can I get back to where I was with the previews working automatically?
I actually rebuilt all 186 previews in the set to 1:1 after your suggestion and the Portraiture edited TIFFs looked right. But I tried a new Portraiture edit and the returned TIFF preview did not show the changes. So I went to Library>Previews>Build 1:1 Previews and tried building a new preview for the one selected TIFF file but it said all were up to date and the preview was not changed. So rebuilding all of them worked, rebuilding just the one did not.
I would try deleting the preview cache, forcing LR to rebuild it. You should only have to do this once.
With Lightroom closed, use your operating system and go to the folder that contains your catalog file, look for a subfolder whose name ends with Previews.LRDATA, and delete the Previews.LRDATA folder. Do not delete anything else. Do not mistake this subfolder with a file whose name ends with .LRCAT which should not be deleted.
I really appreciate your helping me.
I tried what you said, deleting the Previews.LRDATA folder beneath the folder where my current catalog is and the first TIFF file returned to LR from Portraiture worked, but all subsequent ones do not.
Additional related question, though. Deleting the previews folder removed 13GB of content because I have a lot of images. Is there any way to rebuild all of those without having to go open each source folder in LR and asking LR to rebuild the images there? What are the consequences of having deleted the previews cache?
BTW, I happen to have a current LR 5 on my machine that I never use but I tried it and it too does not show the correct preview with Portraiture edits after a round trip.
Any additional ideas?
Lightroom will rebuild the previews as needed, so simply scrolling up and down in the Library Module ought to rebuild the previews, it's a little slow for a while why Lightroom rebuilds the previews, but I've done it, and it's not really too terrible.
But I have no more ideas about solving the actual problem.
Thank you very much.