Two bugs (one which is a big exploit for those struggling against Franz), maybe posted before but since I have slow internet now I'm not going to check all 75 previous pages;
1. In the Berserker Tree, there is a skill called "Primal Rage", which is meant to buff your attack to 400% for the next turn. This is bugged, as when you use it, it buffs your attack to 400% for the current turn (which is useless since you used that turn to use Primal Rage itself), before returning to regular attack next turn.
2. When you have Dennis/Tony in your party and are allowed to grind in the Bloody Corridor before Franziska, you can upgrade their Skill Trees to the point where they can upgrade their class. However, this doesn't upgrade their own class, but instead the main characters.
This can be exploited, since I had already completed the Berserker tree before I upgraded Dennis to Warden. This made my MC a Warden, which I fully upgraded to Knight, which gave me all the upgrades of Berzerker and Warden, up to the Knight class. I didn't try since Tony was out of my party at the time, but I'd bet if you upgraded Tony to an advanced class, you could exploit that to change the MC's class too in order to get all the perks from a third class.
You can probably do this exploit back when you have Llavanya in your party too back in the Emerald Throne, but it would be less useful since your MC's original skill tree probably wouldn't be maxed out by then.
Also, Narcissa best girl and also my wife.