This is part of a wider problem.

Anytime you have a subreport which can vary in length, the section containing it needs to expand to accommodate, and the fully expanded size of the section needs to be known to the higher level (e.g. main) report. If, for example, you have used the "Print next section on same page" throughout your subreport to display it all together, the main report needs to compare the expanded size of the section against the amount of space left before the bottom margin - and start a new page if there isn't enough room (and also print a new page header, or whatever). The size of the section effects anything having to do with pagination, and also several of the checkbox options in the section expert and group expert. If this size is not calculated or not correctly checked, then the related "expert" properties will certainly fail. I have not yet encountered a situation where they work correctly in the context of 2 years of DR development. Has anybody?

Fixed length subreports are OK.