The info node (elisp) Time Parsing suggests that the string "1998-09-12T12:21:54-0200" should be of a format that `parse-time-string` can successfully parse. However, trying to do so produces no useful info from parsing (it returns a list of NILs).

GNU Emacs 26.3 (build 1, x86_64-apple-darwin18.5.0, Carbon Version 158 AppKit 1671.4) of 2019-08-29