Frontmatter doesnt get updated

[xterms]

Suddenly my fronmatter 'icon' property does'nt get updated when I change Icons on pages anymore.
It doesn't matter if I right click on a page in the left tree view and choose option 'change icon' or if I click the three dots on a page and choose option 'change icon'. It doesn't matter if the page have a frontmatter or not nor if the frontmatter have the 'icon' property or not.

Still, the Icon changes when I choose a new one, It's just not showing in the frontmatter.

What I have tried:

• change setting: 'use icon in frontmatter (toggle off -> restart obsidian and toggle on -> restart obsidian.
• Refresh icons from frontmatter (this removes all icons on pages, even those that have the icon property)