Swain Ult+Zhonya's

When swain is using his ult the birds fly to and fro to grand him HP. When he procs Zhonya's close to minions or near something he can leech from he continues to gain HP like he would normally out of Zhonya's. There are no birds and given the nature of Zhonya's I don't think this should continue to be an applied effect through the entire Zhonya's. All you need to do to trigger this is go into game with swain, get a zhonyas and the go into bird form. get near minions and pop zhonya's and you will notice you heal the entire time. If there were birds that flew while the Zhonya's effect was active it may make more sense, it just seems a bit odd.