The only Info I got on the issue is when am Playing on my multiplayer server and turn On creative mode, breaking blocks(mostly plain rocks In this case Granite Rocks) will lead to a game disconnect from the server with that Red Error on the server console. I did notice that it depends on breaking speed if I take a pause between each block break is fine, but if I spam left click to break blocks faster it crashes.
I have a high End Pc, but I still tried reducing View range, Lowering Particle amounts, Reducing graphics, closing the server/game and opening several times and it still happens.
Yesterday it even happened to my buddy playing without creative mode on, He had 2 points in mining faster(Pickaxe Expert) and using the blacksmith class From "MoreClasses_v1.2.5" that increases his mining speed by 50%, and that value was enough to reach a sufficient mining speed to also crash without creative mode while mining rock blocks(fyi I wasn't using any class perk to increase mining speed but creative does allow you to mine faster ofc).
Never had this issue before.
Will upload a List of mods on the server encase you got info on previous casses of Incompatibility.