Viktor hexcore problem

While I was playing as viktor I had already have had one upgrade in the hexcore so It was a hexcore mk1 and I had just got a lot of gold so I went from the First upgrade to the 3rd, which is the final upgrade and It didn't allow me to pick 2 skills to upgrade only one, so I also couldnt upgrade my ult which made me kind of sad. Has anyone else had this happen to them?