Mishap I had, in a manner of speaking (8)
I believe the answer is:
accident
'mishap' is the definition.
(I've seen this before)
'i had in a manner of speaking' is the wordplay.
'i had' becomes 'I'd' (contraction).
'in' is an insertion indicator.
'a manner of speaking' becomes 'accent' (accent is a kind of manner of speaking).
'id' inserted within 'accent' is 'ACCIDENT'.
(Other definitions for accident that I've seen before include "Unforeseen mishap" , "Collision" , "Unexpected incident" , "Calamity" , "Prang" .)