CancelEdit in RowDeletedEvent handler - 2 message boxes

[patrickjozef]

When calling CancelEdit inside a RowDeletedEvent handler, 2 message boxes are displayed.

• A first message box, showing a custom message, which can be configured by the developer
• A second message box, showing a generic message "Delete Selected Features failed"

This is a bit annoying for the users of the addin as they have to click Ok twice. The second message seems redundant to me.
I noticed this behavior when I tried to upgrade from version 3.0.6 to 3.3. In 3.4 I see the same behavior.
In version 3.0.6, only the first message box is displayed, which is the desired behavior for me.

The https://github.com/Esri/arcgis-pro-sdk-community-samples/tree/master/Editing/EditEvents sample illustrates this behavior.
First message box :

Second message box: