The H is probably referring to the Excel column. The problem is that pavlovia imports only the excel sheet of the outer loop, but none of the excel sheets of the inner loops.
My solution was to define the conditions with code components instead of using excel files.
Another potential solution is to create ‘dummy’ loops with zero repetitions at the end of the experiment, and define as conditions all the Excel files you need. Given that they are now outer loops, pavlovia might import them.