[Unity 2018.3] After importing TMP essentials "overrides" show TMP entries you can't get rid of

In case somebody else runs into this problem.
Already sent a bug report so I use the same text for this posting as I used there.


1. What happened
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After importing the "TMP Essentials" which Unity proposes after using Text Mesh Pro the first time newly created prefab instances will show TMP overrides you can't get rid of. (See screenshots showing the steps)

Unity Version: 2018.3.1f


2. How we can reproduce it using the example you attached
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[Unity 2018.3] After importing TMP essentials "overrides" show TMP entries you can't get rid of