Unpredictable change about charge (7)
I believe the answer is:
caprice
'unpredictable change' is the definition.
'caprice' can be an answer for 'change' (I have seen 'unaccountable change' mean 'caprice' so perhaps 'change' could also mean 'caprice'). I'm unsure of the 'unpredictable' bit.
'about charge' is the wordplay.
'about' becomes 'ca' (circa).
'charge' becomes 'price' (I've seen this in another clue).
'ca'+'price'='CAPRICE'
Can you help me to learn more?
(Other definitions for caprice that I've seen before include "'Impulse, whim (7)'" , "unaccountable change" , "Sudden whim" , "Sudden mood change" , "A whim or piece of fancy" .)