We dodged worst rocks: a mixed blessing (3,5,5)
I believe the answer is:
two-edged sword
'a mixed blessing' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'we dodged worst rocks' is the wordplay.
'rocks' is an anagram indicator.
'we'+'dodged'+'worst'='wedodgedworst'
'wedodgedworst' with letters rearranged gives 'TWO-EDGED SWORD'.
Can you help me to learn more?
(Other definitions for two-edged sword that I've seen before include "Something offering both good and bad outcomes" , "One cutting both ways" , "We get odd words (anag) - it cuts both ways" .)