Google Sheet built-in function/custom function order of execution -

my question order of execution between built-in functions , app script functions. there built-in function need executed before rest of app script function(s) executed.

what does

1. data copied first range
2. data copied third range
3. validation rule rejects data in third range because doesn't match data of second range (range blank @ stage because built-in function hasn't executed)
4. built-in filter function executes copies required data first range second range.

what want do:

1. data copied first range
2. built-in filter function execute , copy required data first range second range
3. copy data third range
4. validation rule accepts in third range because built-in function has populated second range.

is there way make happen or google sheets hard wired execute app script functions before built-in functions?

the answer was:

spreadsheet.app.flush();