Frozen Falls boss is bugged

it is almost impossible to kill boss from Frozen Falls map as he just keep repeating this mechanics(1 - when he transforms info frozen mountain, 2 - his projectile attack). I literally can hit him with 1 or 2 attack and than i need to dodge - and eventually he killed me. So basically he repeats actions after 2 second when he finished last one.

Also it was hard to track position as my char and boss models was jumping around - like during high latency - but there won't any latency(no network issues)