Kupietz try dropping the itemprop and seeing if http://validator.w3.org complains or not. I wouldn't trust anything SO says about whatis "valid" or not "valid"
[tantek]
at
2026-03-30 06:21
[edit] Anyone understand what this Twitter service / bot is doing? https://twitter.com/micshasan/status/1459313804915867655
[tantek]1
at
2026-03-28 11:51