native time and snapshot period

I have two different modules. Source is dimensioned by Study top level & using snapshot time (only previous month will populate at the end of every month).

My target module has native time with a subset of active Study.

I want to get the data in my target, if any study has a value in my source that should populate in my target - with snapshot month value. my target line is formatted as snapshot time.

condition should meet this criteria: If the study has a prior value (for example January 2021), (value here is a boolean), if the boolean is checked, in January 2021 it has to give me the value of January only until it is checked the next time that can be in 2025 in my target.

I am using modules with time dimensioned here as well. any inputs is greatly appreciated.