Ever since Nintendo launched the Version 2.0.0 update for Super Smash Bros. Ultimate, some players have been reporting problems with save data corruption. Early reports suggested it was linked to playing certain characters (like the newly launched Piranha Plant) in All-Star Mode or Century Mode, but Nintendo couldn't replicate the bug when they tried.
The latest buzz from Reddit suggests the problem may actually be linked to a specific memory card. While discussing the various save corruption bugs, several Reddit users realized that they all had the same memory card. Specifically, the Samsung 256GB 100MB/s (U3) MicroSDXC EVO Select Memory Card with Adapter (MB-ME256GA/AM).
One user suggested that the problem could be caused by counterfeit cards, but others who have experienced the save data corruption claimed that they took steps to authenticate their cards and they are legitimate. Reddit user rynoweiss posted a screenshot as evidence that he had experienced corruption despite having an authentic card.
It's unclear if everyone impacted by the glitch has the same card or not, but there seems to be a correlation. Nintendo has not yet commented on this new potential development, but hopefully they're a step closer to resolving the issue now.