<human>: The title may be misleading, but my boyfriend's best friend is someone who, as he describes, could be someone who can be relied on, but someone who is also a bit messed up and can cause trouble (e.g. a while ago he was causing drama between two girls, spreading rumors, etc.)

Now, last night I went to a housewarming party; unfortunately my boyfriend wasn't able to go, but I asked a mutual and loyal friend to give me a ride there & back. I told my boyfriend about this, no problems. When I get a ride back, the best friend also comes with us and I get dropped off, followed by him, no problems.

But then for some reason the best friend messages my boyfriend and he says something like this: "Be careful, confusedandhelped looked very sad tonight just got a ride with the mutual friend...." and later said "just kidding"

Now, my boyfriend asks me if this was true and it was 100% incorrect. I wasn't sad, I didn't get a ride with just him, the best friend was there. However, the best friend's message sounded like he wasn't even there (i.e. didn't get a ride).

Even if I did get a ride with the mutual friend, I would have told my boyfriend that and there wouldn't have been a problem. The issue (if it were to be true) would have been that his best friend said one thing while is girlfriend said another. My boyfriend and I trust each other 100%, no problems.

The dilemma I have here is....what the heck is the best friend thinking? That's not even a funny joke, and he has no right to lie about something like that, even if it wasn't true. 

I'm a pretty reasonable person, and I don't mind that the two hang out. My boyfriend asked me not to tell the best friend, so I'm just asking the community for some advice -- should I even be frustrated about this? Should I let it go? Is it normal for a best friend to behave like this?

Thanks in advance.

Can you give me the gist of the text in a nutshell?
<bot>: Boyfriend's best friend sent him a 100% incorrect message that would implicate me as a liar, but said he was just joking. Should I be concerned about this behavior?