@pandakrautThat makes a lot of sense, thanks. I hadn't fully considered the perks for generals yet as I'm only at Malvern Hill. I still feel that's a lot of work to make effective use of the melee perks for infantry. As you mentioned, there's alot of factors to consider before commiting your brigades in battle. This is the reason why I think a balance of speed and accuracy, just like in your playthrough is a better route for me. It's weird because at Shiloh I believed that a mix of melee focused brigades would help deter some of the ai from immediately charging down my line. In hindsight, the accuracy buff would've benefited my brigades a lot more since firepower and positioning are really key to holding off an overwhelming force. Defending with melee units at Gaines mill was also pretty fustrating because those brigades would break and route after getting charged which forced me to counterattack with a reserve brigade. Using those brigades agressively would've been suicide in that spot. Overall, the brigades with accuracy perks consistently outperformed all the other ones by quite a bit(based on the kills and loses stats).
With that said, I found melee cavalry more ideal for charges (in the early game). The manoeuvrability of a large cavalry brigade coupled with the shock perks makes it very punishing for the ai if it were to poorly position its artillery or isolate one of their brigades.
In regards to the bug, well It's the first time that has ever happened. The only way to replicate, will involve me replaying the battle again.