All of a sudden my dvr displays "V2" in upper left of screen

Have you rebooted the DVR?  That would be your first and easiest option.

Thanks!

Yes, the DVR has been rebooted multiple times both on purpose and all by itself randomly.

No change in behaviour.

-weq

Electronic equipment dies and/or starts acting weird.  Who among us hasn't had a phone/computer/TV start doing unexplained things?

If it's bugging you (and it would me), you can call CS and ask for a new DVR.  One would be sent to your for a self-install but you would lose all of your recordings.

Frankly I think the "v2" you are seeing is coming from your tv not uverse.  Maybe the tv was put into some state that makes it unresponsive to displaying the CC.  Check your tv's user manual.

Also what model tv?

Good call @_xyzzy_ 

I blame my lack of common sense on the time change. 

It's not the Display Set ( TV ).  It is definitely coming from the DVR, confirmed via HDMI cable to another display.

CC works fine if I go through the menu to turn it on ( Menu => Closed Captions => ON ).

-weq

I've had Uverse for almost 11 years and have participated on the message boards for almost that long and have never heard of what you speak of but I suppose there's a first time for everything.  *shrug*

Humor us and tell us what brand and model of TV you have.

A screenshot would be lovely, if you can swing it.

My main DVR display is a 65" Samsung unit about 3 years old.  This image is of the Samsung somputer monitor I hooked up to show that the "v2" text is still there and is indeed being generated by the DVR rather than the display.

-weq

The "v2" is always there whether the guide is displayed or not.  The only box that is displaying it is the DVR.  Our other receivers are not displaying the v2.

-weq

I put the guide up there on the picture to show that I took the picture today!

What is the model of the DVR?

Can you get a screenshot of this page? Menu > Options > System > System Information?

I agree with @skeeterintexas.  9 years with uverse and I never heard of such a thing.  At any rate it would be good to do as @JefferMC suggested and post your system info.   Also your dvr model too.

I'd also be curious what happens if you reboot the gateway (pull plug for 15 secs. and let it fully reboot) in addition to the dvr (pull plug for 15 secs.), not just the dvr.

Another experiment I'd be curious about is what happens if you use component cables instead of hdmi?

I did some "research" (and I use that term loosely).  While I found nothing about an onscreen "V2" marking, Samsung TVs do have a feature called screen mirroring.  Since the OP never revealed the model, we can't know if the one in question has that capability. 

I agree that it LOOKS like it's coming from the DVR, but it makes me wonder if the "V2" is short for Video 2 and is an indicator that screen mirroring was somehow activated. 

That's just my 2 cents...spend it wisely.