LMX2581: Question About Lock Detect Output Functionality based on LD_SELECT

Reading the responses from before, I realize one question was not answered. The earlier post is marked resolved so I am asked this question again.  In writing to Reg 6 with LD_SELECT = 4, table 15 shows the register map with RD_DIAGNOSTICS[19:] as one of the terms. There is nothing in the data sheet that says what these RD_DIAGNOSTICS values should be on a write. Are they don't care or all 0's or....  Section 8.6.1.5.1 in the data sheet does show what will be returned in the Readback.