Removing council withdraw access entirely while leaving standard member with draw access in place does not bar council from withdrawing guild funds. When council are barred access they are still able to with draw up to the member limit.

I'm not sure this is a bug. All council/LT are members also. Thats why if the leave a guild they have to resign as member and council.

Yeah, that's not a bug, because they are still members.
The Council withdrawal access is mainly to be able to allow council members to withdraw more than normal members.

Allowing specific bank access levels on a per-person basis on top of the current system would (at a guess) probably fix the problem iry is having that would make him consider this a bug.