Is it possible that the word "union" is replaced with " " when I try to use the [[Url:variablename]] tag?

When I call a page with "test=testing1234" in the url then [[Url:test]] returns "testing1234" as you would expect. But when I pass "test=testingunion1234" then [[Url:test]] returns "testing 1234"

This has broken my application -- please confirm whether or not this is in fact happening somewhere in the xmodpro code. I do not want to have to escape the word "union" -- is this some undocumented sql injection protection?

Help!