11:22 AM PT -- A rep for CBS tells TMZ ... "A network programming timing error ended last night's Billy Joel special approximately two minutes early in the Eastern and Central Time Zones. We apologize to Mr. Joel, his fans, our affiliated stations, and our audience whose viewing experience was interrupted during the last song."

They add, "Due to the overwhelming demand from his legion of fans, BILLY JOEL: THE 100TH – LIVE AT MADISON SQUARE GARDEN will be rebroadcast in its entirety on CBS on April 19th at 9:00PM ET/PT."

Billy Joel and his fans got screwed during CBS' broadcast of his iconic 100th concert -- 'cause it started late, and got cut off early ... something that seriously pissed off viewers.

The singer's performance at Madison Square Garden earlier this year got aired in primetime for a big CBS special Sunday night -- but thanks to the Masters, it was running behind schedule from the get-go ... which meant it had to be chopped off at the end too.

That's exactly what happened as BJ was finishing his concert with a performance of "Piano Man" -- far and away his most famous single -- and as the show/song was coming to a close ... the screen for many viewers, mostly on the East Coast it seems, went black.

Soon enough, some local anchors popped up on the screen and started talking about the Trump trial kicking off Monday ... a jarring pivot in topics for many.

Different local news telecasts began after Billy was cut short ... and one of the on-camera journos in Ohio actually apologized over it on X, saying he realizes people would've much rather have heard Billy finish the show than hear his voice/see his face so suddenly.

Luckily, anyone who still wants to watch the performance -- which was pre-taped -- can just go stream it online now ... but still, pretty damn annoying for the live viewers at home.

As Bill himself might say ... Turn The Broadcast Back On.