Nevermind. There was a background script running in all versions from 2017+ that I wasn’t aware of.
I don’t have this problem with MAX 2020 (it’s only one version I use from 2017+)
but I want to say so that in the script it is better to use the built-in time variables T, NT, S and F (instead of currenttime)
currenttime is technically a published MXS function, built-in time variables are loaded into the SDK (as interface properties)