In the mandalorian season 2 we saw Luke Skywalker return like the jedi we knew him to be from return of the jedi. Along with him came R2D2, who gazed upon Grogu, and after a short moment, looked happy. To me and a lot of fans it seemed like he recognized grogu. I think he actually did. I believe he knew of Grogu, or knew him personally. As Ahsoka Tano mentioned, Grogu was trained at the jedi temple for years by many jedi masters until the end of the Clone Wars (Order 66).

Grogu is 50 years old during 10 ABY, this would make him the same age as Anakin who was born 41 bby. The math adds up. Grogu would have been at the temple around the same time Anakin was, either when Anakin just arrived at age 9, or, during his years as the poster boy for the clone wars. R2 could have known Grogu during this time and seen him training with the other younglings. Now if he did know him, then why didn’t Grogu seem like he recognized R2? There’s a few theories here. One being, his memory was wiped, and this could be interpreted from his memory going dark as Ahsoka said. Now that’s either a metaphor for being mind wiped or losing his memory, or it means things were more literal in the sense that the dark side was around him, and bad things happened. I’m more inclined to believe the first, that Grogu indeed can’t remember somethings, just like he can’t remember much to do with using the force.

I think over time with Luke, Grogu’s memory will be restored and cleared, and we’ll get to finally learn who his parents were, and how he was saved from the temple during Order 66, if he was even there.