Custom Search + Views using custom search path

I just added a custom search path leading to a view in a custom search block.

Example
in the search block I added:
custom/path?keys=[key]|My custom search path.

Senario:
1. Searching the first time leads to a "Page not found" error. ( the URL shows custom/path%3Fkeys%3Dabico )
2. while on the page, searching again leads to the correct page with results.

in case you're wondering I do have exposed filters in my view.
Did I do something wrong here in my configuration?