Is 52C too hot for this LED?
Reliability is ~doubled for every 10'C reduction above room temp . unless there is a process/design flaw.

It's "Watts on the junction in temp that counts.

Tjcn = Pd x ['C/W] on the thermal resistance interfaces between internal chip junction to the ambient hot surface.  Lumen ratings of chips are often done at 85'C junction but it is up to the Luminaire design to add the cost of making a low thermal resistance to the ambient surface.  It could a few 'C/W above the outside surface temp in the junction unless attention details with copper, extreme coplanarity and grease under pressure.