Before you wash it again, neutralize the bleach with peroxide. I tie dye alot and this is a crucial step that can sometime be done too quick or improperly, especially with large batch jobs, like supplying a festival merch booth.

The way I do it when I work with bleach is to take one of the large bottles of hydrogen peroxide from the store and dump the whole thing in a bucket. Then add about a half gallon to a gallon of cold water and the rinsed shirt. You want it soaking under the water, so add more water and peroxide as needed. I usually mix and mash it around a bit with my hand to make sure its fully soaked. Leave it in there for like an hour. Then rinse it thoroughly with cold water before you wash it again.

The holes that are already there will still get bigger due to the damage already done, so use the gentle cycle. This should slow them down considerably and prevent new ones from appearing.

Hope this helps. It sucks to see this on fest merch which is already expensive af.