I have never heard of this, but it certainly sounds like a connection.
How about having her pinch that side before and during let-downs to see if
that prevents it. Also, is she having nasal congestion, allergy symptoms, or
dryness? Treating these appropriately could help.
--for dryness, she could lubricate the tissues with a little Vaseline on a
Q-tip a few times a day
If all else fails an ENT Dr. could cauterize that side
Kim Connor PA-C, CLE