It tends to follow that if it is wet when made then it is wet when defrosted IMO. Use things like ground chia/flaxseed, oats, small uncooked pasta shapes to add to chop mix to help absorb some of this unwanted moisture but I have found that adding ingredients uncooked (where possible) is the best bet. Any cooked ingredients are better steamed or microwaved than cooked in water and leaving to drain a good while before you start processing.
I have noticed that trying to push a pepper through a disc grater on a processor produces more liquid than using a small electric chopper like the Ninja for small batches on pulse. Dont get dispirited, sometimes I am really pleased with my endeavours and others not so.