chess.com is just bugged
for example, if you have a knight and opponent has a rook pawn it will still automatically declare insufficient mating material even though its possible to mate
No, it wont.
What it will do however, if the player with the rook pawn runs out of time, is it will declare a draw due to insufficient material. This is normal practice according to USCF rules which chess.com seems to use as opposed to FIDE.
I may be showing my naivety/stupidity but how did they manage to make 427 moves in what appears to be a three minute game (with no increment)? 
By using "premove". It is a checkbox in the settings dialog.
It allows you to make (attempt) a move before the opponent's move.
Loco
1) No automatic recognition of 3 fold rep draws
2) Same goes for the 50 move draw as above.
You cannot seriously be calling it a bug because chess.com implements those two rules exactly the same as in otb play?
Insignificant by themsleves but combine those with no lag reconigtion and losing time for pre-moves in a bullet game and you will be smashing your monitor in rage.
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Look on the bright side...you won the game! Your opponent should have accepted the draw! :p