We recently encountered a similar issue in Power Pages when trying to open a record in an edit form, resulting in the same error as shown in your screenshot.
We resolved this issue (which seems to be a bug or non-optimized behaviour in Power Pages) by creating a new form via Power Pages Management and mapping the new edit form to the respective entity list.
When creating the new form, make sure to use Query String as the ID.
Please refer to the screenshot below for guidance.
After syncing the Power Pages site, everything worked as expected.
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