Sub report extending to the new page causing extra blank space

The bug comes, only when the sub report ended at the start of a new page.

I have included the pdf files generated and the jrxmls of main and sub report.

Steps to see the issue

0)Please extract sample.zip.

1) Open output.pdf

2) In this, second occurence of title 'Sub Header' in Page 1 starts after the first subreport ends(table with name 'Microbiological' ) without causing any extra blank space.

3) But in the second page, there is a blank space above the first occurence of title 'Sub Header'.

Tried workaround with splitType 'Immediate' , but doesnt work. Checked the data also and it doesnt contain any empty rows.

Can you please tell me that , why it causes a blank space only in the second page , not in the first page.