Please use How to use code fences.
Do you see these errors when you reload the .rules file? If so that’s to be expected. Your running timers become orphaned when reloading a .rules file so when the timer expires it can’t run the code in the lambda because it no longer has it’s context.
The error posted comes from downtimer. And its caused by an evaluation but it’s not clear which of those lines it’s failing on. If this isn’t just caused by orphaned timers, you will need to add some logging to try and identify which line it’s failing on. Given that timer, I would guess it’s in the if statement.