Hi, I found a tiny bugette in v220.127.116.11 pro
I just made a new climate and looking I have file called "Arctic26-dsw.cli.cli.xml.cli.xml" instead of the "Arctic26-dsw.cli.xml" that I imagine is correct. Everything seemed to work with this new file regardless of file extension, although I didn't test it for long.
I was doing a hack job on an existing terrain project and ended up temporarily editing the existing climate instead. I wasn't able to find an easy way to remap the climate on an existing Attribute map without rebuilding the whole shebang from the DM down, so I just hacked the std_snow material to switch in a new texture I wanted to use and regenerated the texture.