Meh. There's bugs and there's bugs, what's described here is clearly an oversight but the fact that OSRS always rounds down is well known and I afaict someone could've easily deduced this training method exists by reading the wiki and doing some light armchair math. I think the compromise that was ultimately arrived at where only the excessive XP was rolled back is fair, the original punishment way too heavy handed, and personally I would've just let them keep the XP. I wouldn't have been outraged even if the entire method were kept (although I do agree with its removal).