Pokémon Go’s exclusive Raid battles, known as EX Raids, are due for a tweak. Weeks after it began testing the invitation-only multiplayer feature, Niantic confirmed on Twitter that it’s heard the negative feedback from players, and is now working on improving the system.

“Trainers, thank you for your feedback on EX Raid Battles,” the studio’s official support account tweeted. “We’re working to improve the invitation system based on what we heard from you.”

After Niantic launched the EX Raid battles in beta last month, the feature quickly garnered widespread criticism from active players. Unlike typical Raids, the exclusive variant requires players to be regular participants in the co-op gym feature. But Niantic seems to distribute the required Premium Raid pass invitations randomly, so even hardcore Raid battlers may not be guaranteed a chance at the harder, rarer version.

The random system meant that some players who only won a single standard Raid battle will win the Premium Raid pass, while others who regularly battled high-level Pokémon at a variety of gyms end up with nothing. But even having a pass isn’t enough to play in an EX Raid, as they’re typically tied to specific locations. In other words, if you won a Raid battle while you were on vacation and received a pass as a result, you may not be able to get to the EX Raid battle spot in time — because it’s back where you won that first Raid battle.

The worst part is that certain legendary Pokémon, like Mewtwo, are only available through these EX Raid battles. If you don’t have an invite, you don’t get to have a complete Pokédex. Them’s the breaks.

It’s not clear which parts Niantic plans to adjust yet, but the studio’s note is a good reminder that Pokémon Go’s EX Raid system was still just in testing anyway. We’ll see how it changes in the coming months.