My almost 4 and a half months old pup has been displaying to me things that worry me. I'm trying to teach her to drop it. I have 2 tugs identical tugs and use the other to have her switch (drop it). When I play tug with her she has been growling and trying to aggressively bite my hand sometimes when I take the tug. Also when I'm dangling the tug toy waiting for her to grab it she has missed and bit my hand instead several times bow. Other than that she's a sweet little baby 99% of the time. Although one time when we were in my room she growled at me a few seconds randomly for no reason. I think I had treats in my hand or something. Are these warning signs? What can I do to teach her to not do these things. I'm not hitting her or hitting her or anything or any negative corrections outside of firmly pulling her leash a little when walking her and telling her no when she does something wrong.