Fans of EA Sports’ FIFA 16 soccer game are in an uproar after a group of players discovered an issue that is potentially handicapping cards in certain situations. And now EA is thanking them for their vigilance.

FIFA’s Ultimate Team mode, which has players collecting cards of players and putting together teams, may hold back the performance of certain kinds of cards without letting players know. In a thread on Reddit, dedicated fans of this mode detailed that a chemistry boost that awards stat improvements to cards that work well together doesn’t apply to some of the best and most expensive cards. This leads to situations where the weaker, more common version of a player is better than the upgraded one because the former is getting the benefits of the chemistry and the latter is not.

We reached out to EA to ask about these claims, and the company did not deny the issue. Instead, an EA spokesperson provided GamesBeat with the following statement:

“Thanks to the FUT community for raising awareness of a potential fitness and chemistry inconsistency in some FUT items. After hearing this, our teams were in over the weekend and continue to thoroughly investigate the information. We will keep you informed with updates from the investigation. Our commitment to a fun, fair, and secure experience in FIFA is ongoing, and as a community your feedback helps us achieve that goal. A special thanks for your continuous efforts across all channels.”

For years, some FIFA Ultimate Team players have complained that their teams of top-ranked rare cards with perfect chemistry often feel sluggish. That starts to make more sense when you see that certain cards are not getting a stat boost.

This is a potentially huge goof for EA because some Ultimate Team players spend thousands of FIFA 16 Points (the in-game currency that enables players to buy cards from one another) to acquire the best cards. And EA sells that currency for real money. You can get 12,000 FIFA 16 Points for $100. Some of the most expensive cards can sell for millions of FIFA 16 Points, and imagine putting 5 million toward a card and not knowing that it won’t perform as well as something much less expensive.

The issue seems to occur for any upgraded versions of cards that are not “day-one cards” that are far more common and typically less powerful. To expose the problem, YouTube user RighteousOnix compared multiple versions of similarly rated day-one and non-day-one cards. Now, the game doesn’t expose how well chemistry is boosting cards, but Onix was able to find that — in the exact same chemistry environment — only the day-one cards were able to perform a specific high-level dribbling maneuver. This suggests that the upgraded cards are handicapped in some way when it comes to chemistry.

You can see Onix’s full investigation below:

https://www.youtube.com/watch?v=XNtZmCOq8Uk