Default Filter is wrong?

Hello,

I have a table generated by DataTables 1.8.2, where I've added filtering to some columns.
One of the columns contains eg "P 1", "P10, "P 2" etc.

When I enter "P 1" in the column filter, it will return all rows that have "P 1" AND "P10".
That doesn't seem right?
It should only return the rows that have "P 1" in the column.

Is this a bug, or is it expected behaviour (why?) ?

Thanks in advance,
Kurt