In 2.6.1, when a CVE Record POST or PUT request has a JSON document that is allowed by the CVE Record Format schema before the call to mw.trimJSONWhitespace, but not allowed by the CVE Record Format schema after that call, then the response code is not 200, but https://cveawg.mitre.org/api-docs does not mention this.
This may have affected date normalization in the sense that these have all-whitespace strings in contexts where the minimum string length is 1:
CVE-2022-27672 containers.cna.providerMetadata.dateUpdated with .188214Z
CVE-2022-38369 multiple dates
CVE-2022-38370 multiple dates
and all three still have dates that are not normalized, e.g.,
CVE-2022-38369
cveMetadata.datePublished
2022-09-05T09:50:09
Incidentally, and this might be unrelated, CVE-2021-34874 still has dates that are not normalized such as cveMetadata.datePublished 2022-01-13T21:43:00.