Picadors in trouble occurring now and then (8)
I believe the answer is:
'occurring now and then' is the definition.
I can't tell whether this definition defines the answer.
'picadors in trouble' is the wordplay.
'in trouble' is an anagram indicator.
'picadors' with letters rearranged gives 'SPORADIC'.
Can you help me to learn more?
(Other definitions for sporadic that I've seen before include "Occasional - intermittent" , "infrequent" , "Scattered - irregular" , "Occurring infrequently" , "Isolated; intermittent" .)