What’s happening?
The height property defined in RTEGlobalConfiguration.json does not take effect on a read-only form, causing some content to not be fully displayed.
Reason:
Misconfiguration of the RTE control
Resolution:
To resolve this, ensure the height property is correctly configured within the "readOnlySettings" section of the JSON, which should be placed outside the "defaultSupportedProps".
See Add the rich text editor control to a model-driven app - Power Apps | Microsoft Learn for more information.