Strange nan errors when mutating immutable struct arrays

Can you post the lines of code you’re showing as text instead of a screenshot? Would make it easier to debug. Also, having a small example that shows the problem would be helpful for debugging (i.e. a small reproducible example, see here).

Are you perhaps running with --fast-math (which can change floating point results depending on the exact code that’s run - such as using a broadcasted assignment loop vs. not using one)?