Takes place during Episode 8 of robots in disguise
So when Sideswipe was telling Bumblebee off for maybe Grimlock was being controlled by another, I saw that Bee got a sort of distant look in his eyes and then sighed and that gave me the idea of him remembering when he was controlled by Megatron in the Prime series
Disclaimer: I do not own anything with regards of the Transformers franchise
"I don't think Grimlock is in control of himself, he wanted to hit me but he couldn't, it was like there was a war going on inside him." Russell mentioned
"Accept it Grimlock is just a bad bot who has been playing us for suckers" Strongarm said
"Whatever is going on our first priority is to find Grimlock and that pod, and bring them both back here" Bumblebee had commanded
"This isn't Grim's fault Bee, What Russell's saying is at least possible, right? Tell me you know that"
Bumblebee took his optics away from Sideswipe, sighed and closed them and walked towards Fixit, yes it is possible and he knew it all too well. He knew the feeling of batting a war with someone who was inside of you trying to take control. For he was also commanded by someone else in his own body. Megatron, and it was all because Bumblebee volunteered to go inside of the Decepticon leaders mind to find a cure for Optimus while he was fighting for his life with Cybonic Plague.
But that only happened because Megatron followed him inside his head when they released the Cortical Psychic Patch. What Russell was describing was almost exactly like his experience sometimes he had control the other times he didn't.
He thought of what Russell had said about what with Grimlock trying to punch him, sure it wasn't a punch but Megatron had tried to make him hurt Rafael in the moment but he too had stopped him. But he had a feeling this was not the work of a Cortical Psychic Patch
So yes he knows that this might be the reason for Grimlock's unusual behavior but he wasn't about to tell his team that this had happened to him, no, he would keep his cool and get everyone back safe and sound with hopefully no mishaps.
He couldn't let his team down and he put the memory in the back of his mind for now. He couldn't let his past control what was happening in the now. He had to do whatever it takes so he hid all of his feelings on the matter tried to ignore Sideswipe and went to Fixit to try to find their teammate and get him back to his normal Dinobot self.
I hope you like this it was just a quick drabble for fun that I thought of when watching the episode