In carpenters blocks V1.3.5 [1.7+] the carpenters trapdoor only acts like a ladder when open if the block is set to be the original solid variant. Any other variants obtained through the carpenters hammer do not have this ability. Is this of design or a bug, because it is annoying me that I can't use the fancy hatches in my build :)

(Only the left hatch works like a ladder, the rest which the styles have been cycled do not)

(Do note that the hatches have been placed on the top side of the block to obtain the ladder functionality)

This is intentional. The other hatch styles are too thick to naturally climb onto from a ladder, so they're not climbable. The solid hatch style was made thinner and climbable to serve that purpose.

Oh right then, this issue can be closed then. It's a shame I really like the look of the other ones ;)