Install on Always on SQL Server

we are running a migration and trying to get the new install to connect to SQL always on server instance. 

During the configuration wizard it constantly fails and we see that its adding the instance name to the always on server name.

alwaysonserver\instance

using the servername\instance name works, but it wont proceed with the always on name (which doesnt work with instance name).

tried to load the sql 2017 client/driver but it doesn't seem to use it.

anyone else get this working?