I've seen this, but it was because I had made a change, then clicked Save and Keep Working. My change had triggered a pipeline, which made another change in the record in the background while my view of the record was before the pipeline. If you try to save the record you're on now, it will give you this message. The pipeline was the "other user" modifying the record.
I have seen and reported at least 4 other bugs in the new forms, so they are definitely not bullet-proof at this point.
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Michael Frishman
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