SUMMARY
Exif Date Time Original does not always update correctly when using maintenance to read from exif to database.  I am not certain of where the problem is.  First the display of the date in the display of photos in an album almost never updates correctly.  When I upload the files to Flickr, often the dates do not reflect the changes I made in the exif data in the images.

DIGIKAM SETTINGS that may be relevant.
Lazy Update is on.  (update manually or on close).
Writing to image files is on.  (No side cars).

WORKFLOW
0.  Digikam Import of old images happened already.  or new images found automatically.
1.  Add GEO location to the images using Geo Photo.  (the maps in Digikam are horrible).
2.  Add reverse geo location, copyright information, contact information, Date Time Original, Date Time Original Time Zone, Date Time Created Timezone to all images with GeoSetter.  (These are cannot be done correctly in batches in DigiKam - see other long standing bugs).
3.  Now on to DigiKam.

STEPS TO REPRODUCE
1. Run Tools Maintainence on the single Album in Digikam.
2. Inspect the dates shown in the icon display for the images of the Album.  If they have all changed, then all is good.
3. On any images that the date is still set to the date time digitized / date time created instead of the date time original, use the metadata editor to apply the change manually (I really shouldn't have to do this step).  -- sub steps.  1.  Open the Metadata Editor.  2.  Check the date time (The metadata editor will usually show the date time original correctly.)  3.  Apply the change.  4.  Hit the next button.  Go to step 2 in this set.
4.  Check displayed again.  Sometimes all the dates will update.  Sometimes they will not.  
5.  If not.  reload the data in Geosetter.  Geosetter will always show the correct date time at this point.

6.  Other post processing in Digikam

7.  Upload to FLickr.  All images that have the correct date time displayed in the Album in Digikam will be correct in Flickr.  Those that do not have the correct time displayed in the album in Digikam may not have the correct time in Flickr.

8.  Keep trying things to get digikam to update the date time original to what should be coming from the image file.
OBSERVED RESULT
 Inconsistent display in the album icon display.
 Inconsistent upload to flickr.
 I have to go through extra steps to try to get the original date set correctly.  

EXPECTED RESULT
After Maintenance is run to read the Original dates from the image files, the icon display in the album should always show the original date time.
The upload to flickr should always have the Original date time set in the image file by GeoSetter after maintenance read from that image files as the date time taken on upload.


SOFTWARE/OS VERSIONS
Windows: 10
macOS: 
Linux/KDE Plasma: 
(available in About System)
KDE Plasma Version: 
KDE Frameworks Version: 
Qt Version: 

ADDITIONAL INFORMATION
Build date: 9/3/2021 7:09 PM (target: RelWithDebInfo)
Rev.: 244c7230b233b845ca7b7c400b74a5d052549434