The bug
Entities and other non-player chat message sources, like the server console, RCON, and command blocks, appear as player heads on the Select Chat Messages to report screen. In case it isn't obvious, these sources aren't players, so they should not appear as players either.
How to reproduce
Create a server, and join the server with two accounts
Run this command:
/execute as @e[type=!player,limit=1] run say Hi there!From one account, navigate to the social interactions screen, and select the ⚠️ icon for the other player
Click the "Select Chat Messages to Report" button
❌ The entity that said "Hi there!" appears as a player
I can confirm this behavior.