I've noticed that when converting certain files, i'd sometimes get incoherent outputs

example:

vertex_position_3d(my_buffer, 0.1100704, 0.07964528, 5.310774E-05);

Not sure where the E comes from but it causes errors as it's unreadable in GML. 

Any idea what went wrong and how to fix this? 

Hmmm... the E at the end of the number  is a power multiplier. So that last number is actually [5.310774 * 10 ^ -5] or [0.00005310774], which is really tiny.

It looks like it's either my program and c# adding that shorthand to save space or it might be the 3D program you are using.

What does the .obj file you are trying to convert look like?