Certain parameters exist with duplicates from other contexts/inheritances. Getting the value from one of these parameters by name is inconsistent because there’s no way to specify which one you’re after. (This has nothing to do with the python version.)
In these cases, you need to use the API to get/set the specific builtin parameter that you’re after. That’s additionally a good idea since you’re already using python in the previous node. Just continue the functionality with the parameter.
This thread has an example for a similar situation.