Why are EXIF data timestamps wrong on many iPhone 15 photos?

I took over two thousand pictures while on vacation in Europe with my partner's iPhone 15 Pro. Going through them now, I see that the timestamps (as stored in the 'EXIF' metadata section of the image) on hundreds of them are completely wrong - they are off by exactly 9 hours, which happens to be the time zone difference between my home in California and the photo location in Europe. Examples (these pictures were all taken in the same general location at roughly the same time and are clearly sequential): - IMG_2011 - EXIF timestamp 02:19:45 (I was asleep at 02:19 local time, so this is obviously wrong) - IMG_2012 - EXIF timestamp 11:25:39 (this is the correct local time) - IMG_2013 - EXIF timestamp 02:25:58 (taken 19 seconds after the previous image but with wrong timestamp) - IMG_2014 - EXIF timestamp 11:28:09 (taken ~2 minutes after the previous image) with correct timestamp All three EXIF timestamps are equally wrong, on the 'bad' images - DateTime, DateTimeOriginal, and DateTimeDigitized. Of particular interest are images IMG_2012 and IMG_2013 - they were taken from the same spot, just 19 seconds apart, but show timestamps 9 hours apart. The GPS location of all the photos is correct - so it's not as if there was no GPS signal at some points in time causing the camera to think it was back in CA. These are outdoor photos so again, no GPS issues. The EXIF timestamps are very important to me for various reasons so this is a big issue. I do have EXIF tools to correct the timestamps, but it is a terribly tedious procedure. I did closely analyze the full EXIF data, and I did notice one thing - for the images with 'correct' timestamps, they show OffsetTime, OffsetTimeOriginal and OffsetTimeDigital as +2:00; and for the images with the wrong timestamps, they show OffsetTime, OffsetTimeOriginal and OffsetTimeDigital as -7:00. I'm guessing these are relative to GMT/UTC, as Spain is currently UTC+2 and California is UTC-7. So something is causing the iPhone to mark half the images with the wrong offset for some reason. Here's a composite screenshot of the two images discussed above (screenshots from the iPhone) that were taken 19 seconds apart. As you can see, the image on the left is showing 11:25am, while the image on the right is showing 2:25am - 9 hours off. Interestingly, they sort correctly on the iPhone despite the time issues. And here's a snapshot of the EXIF data for the above two images: and a snapshot of the GPS data portion of the EXIF data: The "GPSTimeStamp" entry - approx. 9:25 - is the correct 'UTC' time for both pictures. I'm curious to understand how this could have happened, but I guess I also need to find a way to correct the 'bad' versions. Minor update - the first ~1,600 photos on the trip (taken over a 2 week period) have accurate metadata. The first 'bad' timestamp was IMG_1800, taken Sep-20-2024, and was part of a sequence of images taken inside a church in Montserrat - no obvious difference from previous image. For the remainder of the vacation (2 days, approx 200 images), the image metadata was 'mostly bad' with occasional 'good' metadata, but a few sequences of 'mostly good' metadata with occasional 'bad' metadata. The oddest thing is that the 'good' and 'bad' images were often taken in the same location / similar time, which rules out environmental / positional issues. Now that we are back in the US, I have very few new pictures to analyze and the everything appears to be back to normal (but we won't know until we next travel). UPDATE - here's a snapshot of a windows file manager window, showing the 'date taken' information for a sequence of images taken throughout the day (I realize windows file manager isn't always the most reliable indicator but in this case I can confirm the 'date taken' column corresponds to the exif data in the files). The images shown are in chronological sequence. Img_1914 and 1915 have timestamps circa 3am (I was sleeping at that time). Img_1916 has a timestamp 12:24pm and is correct. Then img_1917 goes back to circa 3am, and the images all the way to img_1931 are too early by 9 hours. Then img_1932 has the correct time of 3:15pm, then the images after that are bad again, until img_1939, which shows the correct time of 7:44pm. The images then stay 'good' until Img_1951, which jumps back 9 hours. The 'good' and 'bad' images were in many cases taken in the exact same location, and ALL images have the correct GPS time.