When there are rubble and blood spots in a castle that I have taken over, they have become buildings that I have to remove before they will start to tick down.

Actually, some of this "rubble" was still towers when I took over the castle, which I later removed, so perhaps the "taking over" is not relevant.

The blood spot graphic on the map appears to be both blood and rubble now.
Camp 3531, castle 25,51

I didn't report this at the time it happened simply because i would have been picked apart by the person i was attacking (It's possible! ).

Anyway, i was approaching a castle that had been taken with a lot of rubble (due to walls taken down) already on the slab that became these rubble buildings. I was ready to move onto the slab and specifically the rubble and i was unable to move onto the castle slab at all even though i know for sure that i had more than enough movement points. I think the problem came about because that opponent had built towers in the same turn and the rubble was displaying the ready in X turns things that comes with new buildings and matched those towers. So basically the rubble became an impenetrable barrier that entire turn which is what i would call a bug as well.

I don't think this was the case for me - the buildings had been there for some time. Some were removed by the previous castle owner before I took over the castle and some were removed by me after taking the castle, but either way the rubble became a building and I had to remove it again before it would tick down

Yeah that was the same case as what i described above. All the rubble that was on the castle when it was taken became buildings basically. This by itself shouldn't be happening and can be exploited quite effectively. The bug was further escalated by the fact that apparently these rubble buildings mimic newly built buildings on the castle slab for that entire turn.

Yeap yeap. Yeah coop. Hehe.
But this problem has been here for quite some time now...

Seems now it doesn't even tick down... I took lothar's castle after destroying a wall and barracks... the blood from our troops and his rubble turned into building... so I removed them.... 10 turns later and they're back to being buildings @.@