Stand to drop a testimonial issue (10)
I believe the answer is:
distribute
'issue' is the definition.
(I know that issue is a more specific form of the action distribute)
'stand to drop a testimonial' is the wordplay.
'stand' is a reversal indicator (I've seen 'standing' mean this (in a down clue, letters stand up)).
'to drop' becomes 'sid' (I can't justify this - if you can you should give a lot more credence to this answer).
'a testimonial' becomes 'tribute' (synonyms).
'sid' written backwards gives 'dis'.
'dis'+'tribute'='DISTRIBUTE'
Can you help me to learn more?
(Other definitions for distribute that I've seen before include "spread" , "Hand or share out" , "Give out" , "Deal out" , "Supply" .)