Devices such as comparators, repeaters and observers no longer power solid blocks. While a line of redstone dust into a block still does. This effects related things like pistons as a result.
I was able to find that in the event of a piston you can update an adjacent block and it triggers the power but only for the piston, there is no pass through power to the repeater on the other side of the block as would normally be expected.
Fixed for next snapshot.