What have done wrong in my config: when I get this error: Search results for 's%C3%B8lvpilen'

[Loginname]

magento 1.9.3.6

Have a few products in my shop containing the word "sølvpilen".

This is  what I did:

1. searched for "sølvpilen"
2. I get a list of many products having the word sølvpilen, here everything looks fine
3. I try to change how many products are displayed on each page, then I get this messag " Search results for 's%C3%B8lvpilen'

Think this is an ecoding issue,but not sure, you have an idea? Strange that it worked perfectly until I clicked on change page size.

PS: Sølvpilen is a norwegian word containing the ø char, which is special for norway