Clue: Unintended eating from tins is back happening? Not at home (10)
Answer: SNACCIDENT
Explanation: Definition: Unintended eating

**<= CANS** ("tins", is back) + (in)**CIDENT** ("happening", not IN (at home))
 

 
*"Snaccident" is not in any of my dictionaries, but I think I've come across it before somewhere to mean "absent-minded overeating", like when you open a big gag of crisps, then a little while later realise you've eaten the whole bag (or is it just me that does that?)