When advertising a PROPOSE message for the first block, are we setting PreviousHash to  or make(byte, 32)? I understood from the handout that the latter is true (an empty byte array is reserved for the empty blocks), but, as far as I can see, the reference gossiper sends out PROPOSE messages with a completely empty array.
I noticed this behavior in TestBinGossiper_No_Contention_Block_TLC_Consensus, where my nodes send TLC messages with PreviousMetahash:  (as they simply get the value from the other Paxos messages), while the reference nodes seem to introduce the array with zeroes particularly for TLCs. The test asks for an array of zeroes in the TLC.
Should I send PROPOSE messages with PreviousMetahash set to an empty array and then, if the TLC refers to block 0, replace that with an array of zeroes?