When a file is overwritten in place, the creation date can stay old while the modification date updates, and depending on your Finder column setup you might be looking at a mix of cached metadata versus true modified time. The 27 MB size also tells those three weren’t exported with the same compression settings as the 8.6 MB ones, meaning Photoshop likely reused prior file data instead of doing a clean write.
To confirm, right-click one of the “wrong” files > Get Info and check both Created and Modified dates, then run stat 03.png in Terminal and compare. If Terminal shows consistent modification times but Finder looks odd, it’s metadata/indexing. If the Created date is actually yesterday, you’re overwriting old files.
To fix this, export into an empty folder or enable “Ask When Overwriting” in Photoshop so you’re not writing over existing files silently. If this is happening on an external exFAT drive, that would make the behavior even more inconsistent, APFS avoids this entirely.