From your link - the Amsterdam miracle was similar. http://www.therealpresence.org/eucharst/mir/holland.html
What are we to learn from this one in Dallas?
An affirmation of the Real Presence. Who knows why our Lord chooses to physically manifest Himself in such a visible manner, at a given moment in time.
Perhaps that Lord does not appreciate being plopped into a glass of water to "dissolve" like a tablet of Alka-seltzer.
"What are we to learn from this one in Dallas?"
"To God all moments in time are present in their immediacy."
With apparitions there seems to be a follow-up regional/global tragedy incidence as if the focus was a special call to prayer....is there anything similar when Eucharistic Miracles occur?