So I think I have figured this one out. I ended up changing my approach to call the JobEntry Rest api instead of doing it in a function but had the same issue. I was able to fix it by calling UpdateExt instead of Update. I expect if I called UpdateExt in the function that would fix the function - I haven’t tested this however.
Looks like it is a known issue… REST Services Update vs UpdateExt Methods
Cheers
Brett