@devnihil Many thanks for your reply. Yes, I can confirm we are using the latest version of yoast.
I am not allowed to disclose our url, but here is the relevant snippet:
<script type=”application/ld+json” class=”yoast-schema-graph”>{“@context”:”https://schema.org”,”@graph”:[{“@type”:”Organization”,”@id”:”url”,”name”:”M\u00fcnchen”…
I have substituted our sitename with the word München, but I think you would be able to replicate the issue using any words containing ü.
We look forward to hearing from you.
Very truly yours
PW