Sorry, I need a clarification on what happened.

A single UTXO spent twice on the same block it is clearly not possible. It is a not valid transaction, so it would be incredibly low possibility to happen.
A single UTXO double spend on two chains is possible.
Is this the case?
What is the difference in the two transactions?

• The fees? (after an initial claim of an RBF transaction being bumped up, it appears the was not the case)
  
• The recipient address? Well, this would technically be a double-spend. But is this what happened?

I guess this was intentional.
Please remember today is the  day 21 of the first month of the 21 year after the 2000, the dollar amount was roughly 21 USD...... who bet on the sender on the 21 minutes after 21 hour Time Zone?