I also had problems with my MaxS8 in combination with my Supermicro mainboard. The card was not recognized by the mainboard. Tried a lot of settings, nothing helped. So I got a new MaxS8 and it solved my issue. At the moment I use VDR without virtualization. In the past I used Proxmox with KVM and LXC. But for testing purposes I installed everything bare metal at least for the moment.
Any errors at syslog and what says dmesg?
I don't think that a new bios will help. I also installed new bioses and I also was in contact with Supermicro...
You need to test the cine s2 bare metal to check if it is a hardware incompatibility or a passthrough issue. Maybe you have an unused hdd/ssd laying around, where you can install your guest os and vdr.