BUG HALL OF GRANDMASTERS?!

Hello,

Last Night i tried to do Hall of Grandmasters but 2 Heroes just take no damage.

I have a Poison Build, Do Shaper and Guardians easily, and all heroes of the Grand Masters just Evaporate, almost with hit kill.

This 2 Heroes dont die, and they didnt block the others heroes that come after him.

The link of the "Bug" is here: https://www.youtube.com/watch?v=VD1CYt6cjUk&t=17s

The build is here: https://pastebin.com/fkhs8bUb

I Think that it is a bug, or any mechanic that i dont understand.

There is no bug. They are just tank and have full block + aegis + CI.