I'd like to resurface an issue that was posted here: https://forum.fortinet.com/tm.aspx?m=193895
I've spent the last few months with DNS problems on my laptop, and was finally able to solve them today by having our Fortinet provider send me a copy of FortiClient 184.108.40.2064.
In the newer versions, connecting to SSL VPN immediately breaks DNS that comes from across the tunnel. In my case, I was not able to resolve FQDNs from our domain inside the VPN, nor were DNS Suffixes applying to any nslookups. After downgrading, all functionality appears to be working correctly.
I'm happy to provide any details so Fortinet can patch this issue, as I need to pull people forward in versions shortly.