Welcome to the forum. Look inside their mouth for any lesions, especially under the upper beak. If there arnt any, smell for a foul odor inside their mouth
As for the beak on both birds, get up real close to the beak on each bird and smell the nostrils. Let us know if you smell a foul odor.
If there is a foul odor, it's sinus canker.
If there isnt a foul odor, it could possibly due to inhalation of feed dust or debris from dust bathing. A warm moist wash rag might wipe it off and/or use a toothpick to carefully remove the debris.
However, if there's a foul odor, dont mess with it.