Hi Bill,
I took another look into this, and it turns out there was an unexpected behavior change in the May release. What is now happening is the names are being split into chunks of alpha-numeric characters and then sorted either numerically or alphabetically depending on whether each chunk starts with a number or a letter. Applying that logic to your data, it is seeing your (chunked) names as :
270CA28945_20190823_00_00 -> 270CA28945 : 20190823 : 00 :00
270CA30220_20190823_00_00 -> 270CA30220 : 20190823 : 00 : 00
270CA28944_20190823_00_00 -> 270CA28944 : 20190823 : 00 : 00
The sort is then treating all these chunks as numbers (by truncating at any non-numeric characters), which is turning them all into exactly the same data for sorting - 270 : 20190823 : 00 : 00
There is still something missing in my understanding though, since it should be possible to modify the last chunk of these names and see sorting happening, that wasn't the case when I tested, so I'm continuing to explore.
We are working to fix the implementation and make it more reliable, though it won't be in time for the next release (which is soon).
Thank you to Bill for the nudge, I hadn't realized this change had been made...
Regards,
Matt