The key bind for Start Attack doesn’t do anything after the patch. Attack Target key bind works, but will stop attacking if hit a second time. You can /startattack in macros and that is fine, but that particular keybind doesn’t do anything currently.
Work Around that I shouldn’t have to do.
Make a macro, call it “startattack” or something like that and have it contain /startattack, then logout, close WoW and open the following file for Global Key bindings World of Warcraft/classic_era /WTF/Account//bindings-cache.wtf for Character-specific Keybindings: World of Warcraft/classic_era /WTF/Account////bindings-cache.wtf in any text editor. Search for “bind T” and replace the line with bind T MACRO startattack (“startattack” being the name of your macro). Save file(s), open WoW.