The most common and most likely answer to this crossword clue is the 8 letter word CAPRICES
I've seen this crossword clue in The Times
C
A
P
R
I
C
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S
More clues leading to the result CAPRICES
Buddy explains!

The straight part
We know that "Sudden changes of mind" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sudden changes of mind = caprices.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 CAPRICES mean?
CAPRICES noun- An impulsive, seemingly unmotivated action, change of mind, or notion.
- An unpredictable or sudden condition, change, or series of changes.
- A disposition to be impulsive.
- A capriccio.