The most common and most likely answer to this crossword clue is the 8 letter word BACKSLID
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More clues leading to the result BACKSLID
Buddy explains!

The straight part
We know that "reverted to making mistakes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reverted to making mistakes = backslid.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does BACKSLID mean?
BACKSLID verb- To regress; to slip backwards or revert to a previous, worse state.
- To shirk responsibility; to renege on one's obligations or commitments.