In an amended SEC filing ahead of its IPO, Reddit warned potential investors that "...on March 18, 2024, Nokia Technologies sent us a letter indicating they believed that Reddit infringes certain of their patents. We will evaluate their claims." Nokia, of course, leaned into, ahem, patent licensing and networking equipment as its business many years ago, and reminded people of it with last year’s logo redesign. Companies paying Nokia licensing fees include HTC, Apple, and more recently, Oppo.
It’s not mentioned in the filing, so we can only speculate.
That’s all we’ve got to go on.