Over the past few snapshots, numerous changes have been made to the properties of transparent blocks, with one of the results of this being that certain blocks can now be placed on top of and on the sides of certain transparent blocks which previously could not. Many of the inconsistencies that once existed with these blocks have been patched as a result, although a minor one remains: it's not currently possible to place ladders or tripwire hooks on the sides of redstone blocks.

When compared to ice, packed ice, blue ice, glass, stained glass, glowstone and sea lanterns, the redstone block is the only block which cannot support these two, which is obviously not consistent. The fix for this would be for tripwire hooks and ladders to be made placeable on the sides of redstone blocks.

While this ticket is essentially identical to MC-5850, I'd argue that it isn't a duplicate, given the changes to the behaviour of all other transparent blocks which have taken place over the past few snapshots, the fact that only two out of the four inconsistencies detailed in that ticket still remain, and the fact that the ticket is almost five years old and obviously does not deal with current game mechanics. Tickets such as MC-70057 and MC-146357 have been resolved and fixed without being considered duplicates of MC-9436. It'd be best if someone from Mojang decides if this is still considered intentional behaviour.