That is water in the nares and a sneeze is how she clears it. Her nostrils sit just above the beak, she is burying that whole area in a deep bowl, and some of it goes up. The dunking you mentioned is almost certainly the whole story.
The shape you have described is the harmless one: one or two sneezes immediately after drinking, then normal, clean dry nares, nothing else wrong. A shallower dish fixes most of it, and giving her a separate bath dish fixes the rest, because right now her bath and her drink are the same bowl.