ADMV1014 reserved register values

Hello.

The ADMV1014 has a number of bit fields which the datasheet says are read only.  For instance bits 15:10 and 5:4 of register 0x4:

If I write to these "read only" reserved bits and then do a read back, the reserved bits have change to the value I wrote, suggesting that these fields are actually read/write.

For instance, If I write 0x7FF8 to register 0x4 and then do a read back, I get 0x7FF8.  Clearly reserved bits 15:10 have changed to 0b011111 which should not happen if these bits are truly read only.

Can Analog confirm whether this is the expected behavior?  Even though they are changing, does the device ignore the reserved values, or do I need to set them to the datasheet values?

Thanks for the help