If you say that someone has reverted to type, you mean that they are now behaving as you would expect them to, after having behaved in an unexpected and better way.
[disapproval]
He was adamant that this setback does not mean he has reverted to type.
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revert to type in British English
to resume characteristics that were thought to have disappeared
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Examples of 'revert to type' in a sentence
revert to type
If he was going to be an English gentleman in the rest of his house, he could hardly revert to type in this most intimate of sanctums.