Hi @christiam and @Thyme, this is an issue that came about with the move to a later version of java as the date handling changed from what it used to be (in the java 8 documentation that you have referenced).
@christiam… Did you upgrade from knime 4.3 or 4.4? I think it was probably from KNIME 4.3 as I believe your data would have worked with that version, but not with 4.4 and above.
This was a change in the underlying java date handling and not a direct change in knime. For some locales, the AM/PM now has to be in lower case instead of upper case for the date conversion to work.
There is a config setting that I have detailed in the following post, which you may find of use of this is causing problems…
Hope that helps, and explains why it doesn’t now always work the way you (and I) previously expected.