Interesting, #GNU `date` seems to support dates with ambiguous three-letter offsets, though it's unclear how it decides to disambiguate them. Looks like "IST" defaults to "India Standard Time":
$ TZ=UTC date --iso=m --date="Thu Aug 27 12:34:56 AM IST 2020"
2020-08-26T19:04+00:00
For me "CST" maps to "Central Standard Time" (UTC-5) rather than Cuba (UTC-6) or China (UTC+8):
$ TZ=UTC date --date="Thu Aug 27 12:34:56 AM CST 2020" --iso=min
2020-08-27T06:34+00:00
Interestingly, that time doesn't exist in America/Chicago, but it still applies UTC-5!
Also, who picked that as the default date format? Was it someone trying to make American MM-DD-YY formats look sane?
Day of week, then month, then day of month, then time, then time zone indicator *then* year.
Maybe it came out of a conversation with a frustrated just-arrived time traveler:
"What's today?"
"Thursday"
"No, the date!"
"August 27th."
"Be more specific!"
"Uh... 12:34:56? AM? Central standard time?"
"THE YEAR, MAN!"
"Oh, 2020."