Nintendo has promised to fix an annoying bug that’s cropped up in Kirby 64: The Crystal Shards, a Nintendo 64 game that’s available via Nintendo’s Online Expansion Pack subscription. According to NintendoLife, the bug makes it so players can’t move if they’re hit by certain enemies or items in the game’s underwater levels. The only way to fix it, according to people who say they’ve experienced the bug, is to exit the level.

The issue seems to be caused by Nintendo’s emulator, as players report that they don’t remember it happening in the original version of the game or in other ports (it was available through the Virtual Console on the Wii and Wii U). In a tweet on Friday, the company said that a patch to fix the issue “will be released early next week.”

This is far from Nintendo’s first brush with emulation woes on the Switch. Players have complained that some classic games run poorly on the company’s modern console, and in some cases, players have noticed changes from the original versions. When Paper Mario, another Nintendo 64 game, came to the console, its launch was a bit of a disaster; there were crashes, complaints of lag, and even reports of save file-deleting bugs.

It doesn’t help people’s moods that Nintendo markets its emulator as a premium feature — to get access to NES or SNES games, you have to subscribe to Nintendo Switch Online, which costs $20 a year. Access to Nintendo 64 games, however, requires a subscription to Switch Online plus Expansion Pack, which is $50 a year (and which includes other emulators and access to DLC).

Getting games to emulate properly is no small feat, and Nintendo isn’t the only one that’s struggled. Sony’s PlayStation Plus classic game emulator, meant to run PlayStation 1, 2, and Portable games, has already garnered some complaints, with Digital Foundry calling the current iteration “not good enough.” (Ouch.) People weren’t terribly excited about the emulation capabilities of its standalone PlayStation Classic console either.