_Perhaps_ it wasn't intentional, but it started happening around the time FB started forcing people to use Messenger and now you can't even access messages via the mobile website so who knows.
I haven't used FB for several years now so I'm a bit out of touch.
Perhaps not intentionally broken but I still have issues with double texting on the Messenger mac/web app.
iMessages also has this issues as well... Telegram, Discord, WeChat, MSN Messenger, etc. all seem to have figured out how to prevent double texts from occurring.
