Bugs in code vary slightly

My code tends to randomly vary in different runs with no alterations to it. My initial code isn’t finished yet (can upload a copy below if need be) but it’s getting harder to add more to it due to this variation. Im on the vex vr drawing canvas, and the robot will randomly turn at different angles then given or stop drawing halfway through a line before the pen is raised, and these bugs are inconsistent, It could be a hardware issue with my laptop (my school computers suck), but is there any other fixes I can attempt before assuming this is the problem?