Freeze frame

This is what a television looks like.

It doesn't matter what channel it's on, but as long at the TV is on, it freezes up at 6:58.
Every evening.  Sometimes it is a short freeze like a little skip in the feed.  Other times it fully freezes and we have to change the channel to reset it.
We're not sure when it started, but probably a few weeks ago.

Ross is usually working while the TV is on some show or other, killing time and waiting for Emmerdale to start.  I'm usually in the kitchen working on dinner.

It's gotten to the point that it serves as a nice little alarm for us.
Ross looks up from his work and says, "It must be 2 minutes to 7."

What is this about?
Does it only happen to us?
Is it a time-sensitive glitch in our cable?
Or is it a sign from Sky (our cable provider) that we watch too much TV?

As a bonus, and to save this being a completely pointless post, I'll now discuss the words "Boob Tube".
In America, it's slang for the TV.
In England, it's what I know as a tube top.   It always strikes my ear as lewd when I heard this kind of shirt called a boob tube, though it's a very apt name.  It is, after all, a tube for your boobs.