Creating a new document and adding an empty field with type "Object" then trying to change it to an int32 generates an error "Insert not permitted while document contains error". It looks as though Compass is adding the string value "int32" is added to the field, and so the value is not valid for an int32 data type.

Work around: Change the field type to string, insert an integer value and then change to type int32. You can now save the document.

To reproduce:

• Insert a new document into a collection.
• Create a new field , e.g. "a" and select type as "Object", do not insert any value.
• Change the field type to "int32".
• Error is generated.

Screen grab of issue: https://cl.ly/7031932a2a81/Screen%252520Recording%2525202019-02-28%252520at%25252014.38.gif