I have avoided playing Savage 2 on windows for some time because of this bug, i currently have my charge set to Caps_Lock and block set as Right Click. When using linux this works great but in windows having charge set to anything besides a mousebutton causes you to drain all of your stamina and gives a stutter effect if the charge button is held down too long.
To fix this i used a AutoHotkey script (See Attachment). This is the script.
#IfWinexist, Savage 2 - A Tortured Soul
Very basic, it simply swaps Right Click with Caps_Lock (or the key of your choice) whenever the game is running.
Install AutoHotkey, compile the script, put it in your startup folder and your good to go.
If you are planning on using the same setup i have, Caps_Lock=Charge & Right Click=Block, i will include this script already compiled so you wont have to install AutoHotkey software.
Hope this helps, if there are any questions feel free to ask.