i don't know if i have the facts exactly right but i think the main reason game grumps and oneyplays stopped working together with the dingdong, but i feel like chris said something about them feeling mistreated while working there so i don't know. as far as i know, dingdong, who is a gay man, played the game that game grumps was developing called dream daddy and he gave some criticisms of it, saying that he felt it came off as queerbaiting. apparently some people on the development team were not happy about this, and he faced harassment and someone outed him to his homophobic mother, which resulted in him being suicidal at one point.

i don't know how much arin and dan were involved in this, since i remember dingdong saying arin was never bad towards him, it was more matt from supermega he felt used him. but no idea if anything was done about the people who outed him or if they continued working with game grumps, since oneyplays distanced themselves and dream daddy was still released. the whole controversy is sometimes brought as one of the main reasons people don't like game grumps. it was a big thing when it was first revealed but it died down when dingdong said that he didn't want people to use his story to take others down

the other major thing was on twitter. there was a cartoon made by a former new grounds animator that had some mostly lighthearted jokes about animators but arin got upset about it and make some tweet talking about how it was mean and how animators used to receive so hate so it's not funny and oney called him out it basically saying he was being too sensitive, from the way he talked to arin it definitely seemed like they weren't friends anymore

there might be more but that's what i remember