Different result for same inputs in compute

I just spent a few hours tracking down a bug that was only happening in a compute context.
If I opened the gh file in grasshopper and set the same inputs, some strings and numbers, there was no error. I even placed a breakpoint in the GrasshopperDefinition.cs file to check that the params are the same. The issue was that after a Brep solid difference there was no output, but only in the compute context. I had 2 of them after each other and after switching the order (they both just removed some geometry) the result is now that if works the same.

How is this possible, what can be the cause?
I came across this on other occasions in a different file.


I managed to create a sample gh script that will change it’s output depending on where it’s running. In grashopper, Rhino 7 output is empty. In compute, output is: obj5 is null

Please check it out:

sample.gh (21.9 KB)