SE has decided that they want the playerbase to try to improve itself nothing says get the mechanic right like a one shot mechanic.

This is optional content to boot so they tend to up mechanics more here.

It is week 1 so wiping is expected.

To help understand it you have to pay attention to your debuff and stand in the intersection of where you will get hit by the opposite colour 1st then the same colour second. So say you got the black debuff stand in front of the white birds, check which portal black ones are entering and stand in the square where that portal colour would spit it out, moving up/down in front of the white as needed.

Being normal mode feel free to stop dps here to get the pattern down. It is recoverable with a few deaths just gotta hope it isn't all your rezzers that die.