The weird thing is, my plugin wasn't causing any issues at all when applied to Terraria 1.4.1(.1) using the previous version of TT2 (2.3.1405.1). It was only after updating TT2 to 2.3.1141.0 that my plugin started crashing the game. Not to accuse you of causing this or anything, I just thought that was odd.I've found that especially large methods like DoDraw are highly sensitive to being patched in Terraria 1.4.1 and are more likely to throw off the time-sensitive code than patching a smaller, out-of-the way method would. While I am still trying to figure out exactly where the indeterminate code is in Terraria's pile of spagehetti, I suspect that any method which runs before xna/gdi establishes a d3d device and application window is more likely to change execution time during whatever the critical period is. You may need to adjust your plugins accordingly.
Sticking to smaller methods sounds like good practices regardless.