Channel issue with NDI output on 2.6

I am currently testing 2.6 (Dell R440 with Nvidia T4), and I experience the following : 16 NDI channels defined. They are all visible to NDI Clients in the network. No errors at all in server, but it lays content only up to channel 9, no way to get any content above (channels 10-16 stay black). Any advice appreciated. Thanks for support.