Reapeaters/Comparators update blocks they are facing towards but not others

When placing or destroying a repeater, it will update the block the repeater is facing towards but not other blocks.

Steps to Reproduce

Make a BUD switch.
Place a repeater facing towards a block adjacent to the BUD switch.
The BUD switch will trigger.
If you place the repeater facing any other direction, the switch will not trigger.

Also happens with comparators and redstone torches. Redstone dust will also do it, but only when destroyed.