What can a parent do when their 2 yr old misbehaves by hitting at daycare--but acts fine at home?

My child's daycare teachers report that my little one has been hitting clmates & them-ugh. randomly thru the day, no particular cause--off and on the last 2wks; one teacher in particular is starting to put pressure on me to come up with a solution, in that their only option is to redirect bad behavior. My kiddo is super bright and knows there is no real consequence, so he automatically redirects himself while.... grinning at the staff... in a smart-alec way ( i witnessed this once during pickup! lol). I don't allow him to hit or smart-off--we use the eye-level-warning .... then a timeout if happens again--solution at home if he acts up-which works. They cannot do this at school--timeouts are a no-no, per policy. How am I suppose to help them fix this, when I can't be there in the moment? What can I do to help this go away ? The change may be stress-- one teacher left a mo. ago-coll grad & a new one was hired 2-3 wks ago etc. Is this just a wait it out phase? help, a mom out