Routing Issues with ignoring access tags

But this is a rare feature of Germany and can certainly be mapped.
remember: designated does not mean mandatory

not a oneway case:

bicycle:forward=designated    (because of DE:240)
bicycle:backward=yes             (because of DE:239,1022-10)

you may better (additionally) tag

bicycle=designated
maxspeed:bicycle:backward=walk

in case:

bicycle:forward=designated
bicycle:backward=no

you may better tag

bicycle=designated
oneway:bicycle=yes