I found Hanes tagless, American Apparel, Anvil 980 work best, Gildan for most part are junk.
Worse colors for anyway is: light blue, royal blue, slate, red, orange - some of there turn a bleaches pink.
Some of bella green will bleach to : )
Could be also you putting down to much pretreat, when our Viper does not spray evenly, it will leave certain parts stained.
Brother pretreat is a nightmare alot of times : (
Def. try Hanes brand, never had an issue and are cheap.