Problems sending media through Facebook messenger

Recently, I have been having trouble sending pictures to people through Facebook’s Messenger app (https://www.facebook.com/messages). For a while, I had just been ignoring the issue, as I expected it is just a temporary thing with some Facebook update or whatever… which turned somewhat true. My recent investigations into the problem seem to suggest that the issue has to do with both Facebook, and the specific browser release of Brave.

More specifically, I have this problem when using Brave on Linux (newest version of Linux Mint), where I have it installed through the flatpak. I have discovered that I only have issues with sending media in the new End-to-end encrypted chats in Facebook. It also doesn’t seem to be a full-on issue with Brave itself, as I have no trouble sending stuff when running Brave on Windows. Rather it seems to be a problem with the Linux/Ubuntu/Mint distribution specifically. Also, it doesn’t seem to be affected by Brave Shields, as disabling it results in no difference.

Does anyone know whether a specific configuration of the browser could solve this problem, and if not, is it possible for a fix to this problem be implemented in future releases of Brave’s Linux Mint version? I am unaware whether the problem is present on other Linux distributions and don’t have the time to test this. Maybe other community members could.