This looks to be correct behaviour, javascript agrees:

I think this is as it comes after the #, which is considered the anchor, which always has to come after the query string, and since it sees the # it considers that the anchor rather than the query string as you'd expect

Source

i.e. the Anchor for this URL is /1?query1=test. It would have to come before the # in order to be parsed as the query string.

Hope this helps :)

Thanks a lot @Snaddyvitch-Dispenser
I was confused with # it's clear now.

Closing this issue