Anyone else recieving nonsense IM's?

In the past week-ish, I've had random im's that really don't make any sense. Some are from friends, some are not.
They contain just strings of numbers or similar.. nothing that makes sense and the sender doesn't seem to know they're doing it. Yesterday I seem to have sent some gibberish too.
Not sure whats going on, my first thought was a spamming object/attachment but even those make sense.

i did a couple of days ago but in open chat, albeit it was someone i know, and i thought it was odd but i didn't ask if it was a joke (that was my thought at the time), because i was busy iming and just brushed it off
it happened more than once, all in the same day - nothing since
i do remember at the time people complaining about the lag - don't know if that is related or not

Have you been playing with the Emerald viewer, especially switching between it and others? Recent versions try to use OTR encryption by default, and sometimes those can leak through to offlines, rendering them unreadable. (The first few characters of the message would include "OTR" if this is the trouble.) You shouldn't see messages like that if you don't use Emerald, even if others you talk with do.

If that turns out to be the problem, you can disable OTR: Preferences->Emerald tab->IM sub-tab->Decline Use of OTR.

If you haven't been using that viewer, then something else odd must be happening... is there a sample you would feel comfortable posting?

Thanks for the reply. I am using emerald so that may be the problem. otr has now been turned off, so lets see...