filter is not working for combination of integer and datetime columns as expected

Smartclient version: 8.2 , 10.0
Browser: Mozilla, IE
filter is not working properly for combination of datatype integer and datetime columns.

I have two columns in the grid. date and file size.When i filter based on file size it matches as 'LIKE' works in MYSQL. But when i filter based on date and file size, i need to provide exact file size. why is this behavior observed?