Actually, it bothers me, too. I participated in 4 facebook companies and all of them were extended for two months. It makes me worried, considering the payments won't be coming soon either. 
all of them ? i think that is not a co incedent anymore . if i were you id better quit on it because it is clearly obvious that you joined a scam campaign and soon your efforts will become wasted if ever you still insist to continue .
Actually most of ICO are extending their bounty campaigns so it's not a scam but unfortunately it's the ICo crysis that requires to extend their campaigns otherwise project won't reach softcap...
no there arent . not all ico's are extending their campaigns because not all ico's are going to be succesful plus , running a campaign isnt also cheap .
almost all bounties usually will run 2 to 3 months and this is already long imo , that why there's no really need for further extension not unless they are paying upfront of per week via btc/eth .