Ok so that is the same a mine. You should not need to reboot but may need to flushDNS. If you want to reboot that is fine. A issue I did have was the 1st connection I had random IP and mac address enabled(IOS does have it as default) and I did mistakenly add that one.
I just want to make sure I understand: The Iphone is set to not use vpn but still connects using the vpn, as apposed to the iphone can’t leave the LAN or use the WAN, gets no connection.
I also want to make sure that you are hitting apply when you add the iphone to the MAC exclusion(I have not done this a number of times)