We did not test LLDV with the first version but @GREMez comment is about it.
Interestingly, it may be a different problem than the one described in Vincent video because with the Dune player set to LLDV in the display settings(instead of using the vertex), now L1/L2 is working.
There are no LLDV options on the Shield/x700, it can only be forced with an hdfury device or a LLDV TV.