This same thing happened to me just yesterday with my shutoff valve under the sink. I had to replace a small leaking PTrap washer and I noticed small drip coming from the sharkbite shut off valve. I have also sworn by these and I know this was replaced right before we moved along with all the sinks in the house. As soon as I touched the valve it started a steady drip. Glad I was already down there and I just switched to compression and not push in.