IRS to Dez Bryant -- You Dropped the Ball In '13 (Update)

3:23 PM PT -- Bryant's rep tells us ... Dez was notified about the lien in June 2015 and cut a check to the IRS on July 1, 2015 to clear it up.

Bryant's rep insists the lRS released the lien on September 16th, meaning Bryant is now officially off the hook.

9:56 AM PT -- Bryant's rep, Ron Berkowitz, tells TMZ Sports the Cowboys receiver has handled the situation ... saying, "Clearly, this was an oversight. Once it was brought to Dez's attention, he paid it in full."

Seems Dez Bryant threw up the X to Uncle Sam back in 2013 ... failing to pay roughly $80,000 in federal income taxes ... this according to official records obtained by TMZ Sports.

The IRS filed a federal tax lien against Bryant in Dallas ... claiming he never paid $79,274.75 in income tax for the money he made back in 2013.

Seems like chump change for Bryant now thanks to his new $70 million deal ... but back in '13, Dez only raked in a measly $1.8 mil, according to Spotrac.com.

We're guessing it's just an oversight on Bryant's part ... but you don't wanna play around when it comes to paying the tax man -- just ask Wesley Snipes.