Repeater not correctly detecting redstone signal through block

Repeaters become powered by redstone wire through a block no matter the redstone's signal strength as long as it is > 0 as shown in Image 1. However, if you build a pulse extender as in Image 2 and press the button to activate it, the repeater will only become powered for as long as the button is pressed. It will not detect and be powered by the changing redstone signal of the pulse extender.