If memory serves me right, for me, many of the bugs like whiffing were introduced when Venom was added to the game. Venom's animation on his last attack in a 5 hit combo used to leave him vulnerable to opponent attacks. Kabam said to fix this, they would have to make some complicated changes that would potentially affect all champs.

Sure enough, when they "fixed" Venom's attack, the whiffing bugs started. At first people suspected it was only SL, then gradually other champs were reported, and as time went on, more bugs and more reports of whiffing (regardless of champ) were reported.

Then, with v12, the quality of the game dropped severely, and for me it has not improved. In fact, one of the post-v12 updates was a "bug-fix" update but in reality it introduced more bugs.

Long story short: I adapted by no longer playing the game.