I think this could be more a case of ambiguity in the kit description, rather than an outright bug. I think the 'cannot cast detect evil' bit is actually referring to not having Protection From Evil as an innate ability, like normal paladins do. Same thing goes for Detect Evil.
Of course, one could argue that an evil character like a blackguard still shouldn't be able to cast a Good-themed spells like Detect Evil/Protection from Evil, but evil clerics are able to cast them as well.
Comments
Of course, one could argue that an evil character like a blackguard still shouldn't be able to cast a Good-themed spells like Detect Evil/Protection from Evil, but evil clerics are able to cast them as well.
Disadvantages:
Must be evil.
May not cast Detect Evil.
May not cast Protection from Evil.
May not use Lay on Hands ability
Seems pretty explicit to me