[lscharen]

  The states decided to add one digit to these numbers to further subdivide
  them. They did it differently, of course, and some didn't subdivide at all.
  Some of them have typos with "O" in place of "0" in a few places. Some
  states dropped the leading zeroes, and then added a suffix digit, which is fun.

Any identifier that is comprised of digits but is not a number will have a hilariously large amount of mistakes and alterations like you describe.

In my own work I see this all the time with FIPS codes and parcel identifiers -- mostly because someone has round-tripped their data through Excel which will autocast the identifiers to numeric types.

Federal GEOIDs are particularly tough because the number of digits defines the GEOID type and there are valid types for 10, 11 and 12-digit numbers, so dropping a leading zero wreaks havoc on any automated processing.

There's a lot of ways to create the garbage in GIGO.