CAM limit is not honored in the following situation.

Imagine this scenario.

DVB cards available.
Card A - transponderA=channelA, channelB (cam limit 1)
Card B - transponderA=channelA, channelB (cam limit 1)

(channelA is the same channel on both cards).

At first make that no timeshifting or recording is ongoing.
Then goto tvhome->tvguide
from there start any recording on channelA

setuptv on server now states this
CardA - recording channelA
CardB - idle

so far so good.

Now from tvguide, start a recording on channelB.

setuptv on server now states this
CardA - recording channelA
CardA - recording channelB
CardB - idle

WRONG!!!

It should be;
CardA - recording channelA
CardB - recording channelB

Well channelB is indeed on the same transponder on cardA as channelA is on --- buuuut, since cardA has a cam limit of 1, then it's out of available decryption slots, so instead it should use cardB - since it is free and available.