After one female goes astray, it's as expected (2,6)
I believe the answer is:
of course
'as expected' is the definition.
(I've seen this in another clue)
'after one female goes astray' is the wordplay.
I cannot quite understand how this works, but
'one' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
'female' could be 'f' (abbreviation) and 'f' is located in the answer.
The remaining letters 'course' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for of course that I've seen before include "need I say" , "Naturally, as one would expect" , "'Naturally, as might be expected (2,6)'" , "Naturally, certainly" , "Without a doubt, as was to be expected" .)