Am I retarded?

[Nully]

Am I being retarded with this, or is it a legitimate bug?

So I join a faction (The North in this case), and all is well.

Then suddenly, I notice that all the Lords of the faction (and every other faction) become hostile towards me. I can no longer enter cities/towns that were once friendly, because I am only able to meet with the commander or besiege it. My own faction's Lords give me the option to make peace with them, as do all other faction Lords.

What's going on?

[Heaux]

Did you kill any lords?

[Nully]

Did you kill any lords?

I killed Lord Justyn Serrett.

Is this why?

... if so, can the effects be reversed?

[H3YimDR3W]

Did you kill any lords?

I killed Lord Justyn Serrett.

Is this why?

... if so, can the effects be reversed?

Yes that is why, and it can't be reversed. You'll have to win them all back over.