Didn't use an flux:form.container for some month now, but on the latest v12 version it's broken.
I used it as always:
<flux:form id="testimonial" options="{group:'rxgrid',icon:'EXT:herzog/Resources/Public/Icons/Content/Testimonial.svg',Fluidcontent:{hidden: 1}}">
<flux:form.container name="settings.testimonial" label="Testimonial">
<flux:field.text label="Text" name="text" enableRichText="true" richtextConfiguration="rxminimal-h3-link"/>
<flux:field.input name="name" label="Name"/>
</flux:form.container>
</flux:form>
It now throws an exception when editinng that content element: exception
I'm on TYPO3 12.4.8 with Flux 10.0.7. Any suggestions?