Clearing Crop?

Hi, I have several cockatiels. They are approximately 2 years old. I have had them since they were 2-3 months old. One I have had since it was a baby. It is hand-raised. Since I have had the cockatiel that is hand raised, it has always had very pink nares. It has always been very active and playful. One thing I have noticed that she does that the other cocktiels don't do, is occasionally she will tilt her head back and open her mouth and sit with it open, and while she is doing this, occasionally she will swallow. I have noticed her doing this not very often, but maybe 3-5 times in the last year.

I talked to an avian vet over the phone about the nares being pink, (the front desk, not the vet itself), and she said that as long as her behavior is normal, not to worry about it. She does not do the head tilting very often, but I am wondering if it is normal? She tilts her head back, and opens her mouth, and her throat is open, when she breathes I can hear a little wheezing sound, but only while her mouth is open. Never at any other time. Twice some clear liquid came out of one of her nares, and her eye got watery.

She has never had a discharge from her eyes or nares ever. Her droppings are normal. And she is playful and active. After that happens with her (head tilted back and mouth open), she swallows a couple of times and it is over. She goes right back to eating again. Like normal. What do you think? Do I need to take her to the Vet?