subreport spans multiple pages when saved to pdf

hi we run 2016 enterprise. i have a master report calling my subreport multiple times.

i should start with the sub. when i run it stand alone and save to pdf, it spans multiple pages which dont want. the sub's report page size shows 8.5in, 11in in the properties. and 1 inch all sides margins.

the body is basically 3 rectangles. and its properties show 6.5in w, 6.05256in h.

the top rectangle's properties show 6.5inw, 0.48833in h. the middle (which i dont believe) which contains 2 tablix side by side shows 6.47161in w, 2.38542in h. another answerer said the way i size this rectangle would stay constant so i could insure my bottom rectangle will align near the bottom of the page. but there is no way that height is what i sized it to.

there is one row of independent text boxes below that with a little gap before the last triangle. the last triangle shows properties of 6.49049in w, 2.0625in h. which matches my spec because it needs to be torn off later when a page is printed.

so before i get into the weird behavior coming from the master , how can i get this sub on one page in pdf?

each rectangle specifies keep contents on a single page. while i dont have a printer i can pringt to from the browser, i can print the pdf to paper and will see if perhpas the tablix is extending the page somehow. te right side tablix is meant to take overflow from the left one so everything can stay on one page.