Did you get a response from Mark on this?
If not, please post the TRV file here with a note about which blocks.
Beginning in TPC 2019 R1, block objects can reside on their own layers. So you want to give some thought to how blocks will react to turning layers On/Off if you create them this way.
Most of the time, we create blocks, like details or title blocks where all the objects in the block reside on a single layer.