Brand new Kohler toilet installed with new pvc soil line and floor flange. After about 2 weeks I noticed a stain on the ceiling tile below the toilet. I saw a very small drop of water on the elbow and traced it to where the floor flange attaches to the ell. I used a flux brush to apply more glue around the seam and I thought I got it. But after about 6 hours a little drop appears. It does not leak when flushed I made sure to check on that. Has anyone ever heard of this? Any ideas for a fix?