Just to add my two cents to this issue, this sounds a lot like you're running into a numerical issue. This basically means your system makes an error during the calculation. This is completely normal and taken into account by most software.

The IEEE754 standard defines the minimum precision for floating point calculations. It doesn't define a maximum precision. Therefore, different CPUs may produce slightly different results for the same computation / code. Adding numerical instability, those errors can get large, fast. FA deals with this using strict / stable floating point calculations. (I think they don't do floating point, they do fixed point math)

The issue now arises when there is some aspect of the way your non-x86 CPU works that wasn't anticipated by the developers of FA (e.g. when computing a sine/cosine as mentioned above), that causes your system to make a different calculation error than everyone else. Then you get a different result and a desync.

If those speculations are correct, that would make it nearly impossible to run FA on a non x86 chip to produce the same deterministic results as on an x86 chip.