I’m receiving read receipts from Android and non-Apple users. How is this possible?

I noticed that I’ve been receiving read receipts from Android and non-Apple users on one of my devices. I thought that iPhone’s could only receive read receipts from other iPhone’s or Apple devices if they had that feature enabled? I’m absolutely positive that these people do not have an iPhone and have Android phones. How is this possible? Could it be due to a messenger app that I have linked with my phone or phone number? Can someone please explain in detail the way (or multiple ways) this could happen? I’m so confused and really need to know why this is happening. I’ve attached a few photos to show exactly what’s happening and what it looks like.