We have a leak in our kitchen ceiling. the upstairs bathroom is directly above the kitchen. It's a few ounces of water that occurs infrequently. We removed the ceiling and it seems as though the leak is coming from the toilet waste pipe. One time we were able to cause the leak by flushing the toilet. However, the leak does not occur every time the toilet is flushed. It seems as though there was some fluid around the base of the toilet. Also, the toilet runs and makes bubbling noises (don't know if those issues are related to the leak or are separate issues). Could the wax seal be the cause of this? Is there another likely cause?