I’ll link a few relevant posts here for informative purpose:
https://forums.unrealengine.com/t/how-to-report-suspected-piracy/10614
Illegal (stolen) asset in the monthly free selection - #17 by spacegojira
UE4 - Anti-piracy BP time bomb with real date for Steam? - #20 by DraxFX
REDACTED - Pirate website reselling Marketplace assets - #2 by anonymous_user_b9532c9a
https://forums.unrealengine.com/t/they-might-be-giving-away-assets-that-are-usually-paid/766446/2
Piracy & Technical failure after launching my game. - #16 by The_Gametist
Things need to change. What’s the point otherwise?