Contents contain extra space at end

Hello,
I have noticed that when I sort through PDF files, that the condition "Contents" and then "contain" does not leads to results when the search term has no space at the end but the target in the PDF does.
E.g. if I search for "invoice", it will not find any matches if in the PDF file it is "invoice ".
Only when I search for "invoice " (with the space) it will lead to a result inside the PDF.
For Contain Match I would understand this, but not for Contain only.
Solution / workaround is having 2 condition in a nested condition, one with and one without a space.
Is this a bug or desired functionality?
Thanks,
Etienne
I have noticed that when I sort through PDF files, that the condition "Contents" and then "contain" does not leads to results when the search term has no space at the end but the target in the PDF does.
E.g. if I search for "invoice", it will not find any matches if in the PDF file it is "invoice ".
Only when I search for "invoice " (with the space) it will lead to a result inside the PDF.
For Contain Match I would understand this, but not for Contain only.
Solution / workaround is having 2 condition in a nested condition, one with and one without a space.
Is this a bug or desired functionality?
Thanks,
Etienne