Adjust Date and Time issue

High Sierra 10.13.2, Photos 3.0 (3251.12.190)

I have some photos that when imported, did not get a time zone assigned. Does anyone know a way (via AppleScript or 3rd party plug-in) to see the time zone data on an image? This is causing a lot of my photos to display out of order when sorting by time. For example, a picture at 605pm may show after a picture at 610pm if the 610pm picture is lacking a time zone.

I know that the behavior of the app is supposed to assign the time zone of the computer at the time of import (if it can't figure out the time zone from the picture). In this case, I've used EXIFTool / GraphicConverter to see inside the data of the files - they all have the same information - they were all taken with an iPhone within a few minutes of each other - they all have GPS data in generally the same location.

For information...

1) I've tried changing the way the time zone display shows up (via System Preferences, Date & Time, Open Language & Region..., Advanced, Times, and then dragging the time zone indicator to the short and medium time formats). When I do that, the time on an image shows my home time zone regardless of the time zone shown in the Adjust Date & Time window.

2) Some pictures DO NOT have a time zone at all - meaning that no time zone shows in the Adjust Date & Time window, but there is a time stamp, just no time zone.

What I'm hoping to do is avoid a manual review of every photo in the library to see which ones are missing the time zone - it would be a nightmare to click on every photo, then click on the menu item, then adjust if needed, then save, etc. What a mess.

Ideally I would use a plug in that could update the Photos App with the correct time information and time zone information at the same time. Or, if I could use some type of AppleScript to find just the images with "null" time zone data, at least I could fix them manually, not easy to do, but better than current situation where photos are sorted out of sequence due to missing metadata.

Dane

PS - I do have an active case with Apple on the issue of what is happening, but that is likely to address the issue going forward. I am able to recreate the situation in the Sierra version of Photos, and the High Sierra version of Photos in new libraries, etc. I'm hoping someone on this forum can help me figure out how to find and ultimately fix the ones that are messed up without the massive manual effort that would be required.

Thanks everyone!