Presuming that you are Rock, then it must be in a script that you have loaded. Where you have to go to stop this is in the Remotes section, Alt + R. However, that's as close as I can tell you, since I don't know what script is causing this, and yes it is a script doing this, since the only other alternative is for you to be setting it manually, in which case you would know.
The fastest way to stop this, is to type /!remote off
One alternative is to unload all of your scripts, then re-load them one by one until you find the script that is setting the mode, but this is a slow process.
Another method is to open your Remote Editor (Alt + R), then press Ctrl + F (for find), then search for one or more of the following:
mode $chan +o $nick
mode # +o $nick
on *:join:#
on @*:join:#
on 1:join:#
on @1:join:#
That is not a complete list, but those are the most common formats of the section of code that you're looking for.
Just read your reply and decided to edit my reply:
a deop code would look like this
on *:op:#:{
if $nick != chanserv {
.mode $chan -o $opnick
}
}
That will deop anyone that is opped in the channel, unless it was chanserv that gave the ops.