Season 3 of Stranger Things has been out less than a week. However, over that time, fans have watched — and re-watched — the hit sci-fi series set in the 1980s. As a result of this, some fans have noticed a gaffe by way of product placement.

SPOILER ALERT: This article discusses Season 3 of Netflix’s Stranger Things . Please proceed with caution if you have not yet viewed all available episodes and wish to avoid spoilers.

Eagle-eyed fans have taken to social media in order to point out a mistake in Season 3 of Stranger Things . In Episode 5 of the hit sci-fi series, Mike Wheeler (Finn Wolfhard), who has been having relationship troubles with Eleven (Millie Bobby Brown), offers her some M&Ms that he got from a vending machine. In the briefest of moments, Mike is seen pouring some of the chocolate treats into Eleven’s outstretched hand. It is at this moment that many fans noticed a red M&M.

Considering Season 3 of Stranger Things is set in 1985, red M&Ms should not be available. Fans immediately took to Twitter in order to discuss the mistake.

“SPOILER ALERT: Massive time/space continuum error in STRANGER THINGS: SEASON 3,” Exhibitor Relations Co. said in a tweet .

“Nearly blows apart the fabric of the entire series. In episode 5, at the hospital, red M&Ms show up. This is 1985. Everyone knows they were on a 10-year hiatus & didn’t come back until ’87!? Boom.”

The official Twitter account for M&Ms also tweeted about the mistake.

Clearly, in 1985 Red M&M’S were around…. in the Upside Down. #StrangerThings https://t.co/585CSb26T4

— M&M’S (@mmschocolate) July 9, 2019

So, Why Weren’t Red M&Ms Available In 1985?

As Comic Book points out, red M&Ms had been removed by Mars Inc, in 1976. This was due to the controversy involving red food coloring FD&C Red No. 2, also known as amaranth. In 1971, Russia had done a study into the red coloring suggesting links to cancer.

At the time, red M&Ms were not colored using the red additive involved but, because of the potential links to it being a carcinogen, Mars Inc. decided to remove the red M&Ms regardless, in order to avoid confusion with their product. As a result of this change, orange M&Ms were added to replace the red ones.

As CNN points out, Red M&Ms did a make a comeback, though. However, this was not until 1987, two years before the events that unfolded in Season 3 of Stranger Things . So, 11 years after Mars Inc. dropped the red M&Ms, they were returned to packets due to customer demand. Mars Inc. also decided to keep the orange M&Ms.

Of course, considering the M&Ms Mike offered Eleven came from a vending machine, it could just mean that it was just a very old packet of M&Ms.

All three seasons of Stranger Things are currently streaming on Netflix.