The most common and most likely answer to this crossword clue is the 8 letter word SLIPPAGE
I've seen this crossword clue in Independent
S
L
I
P
P
A
G
E
More clues leading to the result SLIPPAGE
Buddy explains!

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 SLIPPAGE mean?
SLIPPAGE noun- The act of slipping, especially from a secure location.
- The amount by which something has slipped.
- A lessening of performance or achievement.
- A decrease in motion, or in the power of a mechanical system due to slipping.
- The difference between estimated and actual transaction costs.