Ctrl z or undo functionality not working on paragraph in Designer

It happened a couple of times now… but I can’t use the ctrl z function in a paragraph in the designer… For example: when I cut a text and place it again, I’m unable to do so.
I can’t use the undo/ctrl z function… I need to refresh the page, but the text is saved… and I lost my text in the progress…

Error in console:

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