If so, it must have happened very recently. As recently as 2003, the other traditionalist pilgramage there, the Pilgrimage of Reparation, held the TLM in there.
I should have been more specific...they don't allow the SSPX to conduct Mass inside the Colliseum. I believe the SSPX now has an outdoor Mass off the grounds of the Shrine somewhere.
If so, it must have happened very recently. As recently as 2003, the other traditionalist pilgrimage there, the Pilgrimage of Reparation, held the TLM in there.
Maybe they just don't allow the SSPX to say a traditional mass there. I believe the SSPX must say mass in a field.