Nah. This is not even an edge case. You should try making a simple file along the lines of:
PASS oauth:xxxxxxxxxxxxxxxxxxxxxxxxxxxx
NICK yourchannel
CAP REQ :twitch.tv/membership
CAP REQ :twitch.tv/tags
CAP REQ :twitch.tv/commands
CAP REQ :twitch.tv/tags twitch.tv/commands
PRIVMSG #yourchannel :1
PRIVMSG #yourchannel :2
PRIVMSG #yourchannel :3
PRIVMSG #yourchannel :4
PRIVMSG #yourchannel :5
PRIVMSG #yourchannel :6
PRIVMSG #yourchannel :7
PRIVMSG #yourchannel :8
PRIVMSG #yourchannel :9
PRIVMSG #yourchannel :10
PRIVMSG #yourchannel :11
PRIVMSG #yourchannel :12
PRIVMSG #yourchannel :13
PRIVMSG #yourchannel :14
PRIVMSG #yourchannel :15
PRIVMSG #yourchannel :16
PRIVMSG #yourchannel :17
PRIVMSG #yourchannel :18
PRIVMSG #yourchannel :19
PRIVMSG #yourchannel :20
PRIVMSG #yourchannel :21
PRIVMSG #yourchannel :22
PRIVMSG #yourchannel :23
PRIVMSG #yourchannel :24
PRIVMSG #yourchannel :25
PRIVMSG #yourchannel :26
PRIVMSG #yourchannel :27
PRIVMSG #yourchannel :28
PRIVMSG #yourchannel :29
PRIVMSG #yourchannel :30
PRIVMSG #yourchannel :31
PRIVMSG #yourchannel :32
PRIVMSG #yourchannel :33
PRIVMSG #yourchannel :34
PRIVMSG #yourchannel :35
PRIVMSG #yourchannel :36
PRIVMSG #yourchannel :37
PRIVMSG #yourchannel :38
PRIVMSG #yourchannel :39
PRIVMSG #yourchannel :40
PRIVMSG #yourchannel :41
PRIVMSG #yourchannel :42
PRIVMSG #yourchannel :43
PRIVMSG #yourchannel :44
PRIVMSG #yourchannel :45
PRIVMSG #yourchannel :46
PRIVMSG #yourchannel :47
PRIVMSG #yourchannel :48
PRIVMSG #yourchannel :49
PRIVMSG #yourchannel :50
PRIVMSG #yourchannel :51
PRIVMSG #yourchannel :52
PRIVMSG #yourchannel :53
PRIVMSG #yourchannel :54
PRIVMSG #yourchannel :55
PRIVMSG #yourchannel :56
PRIVMSG #yourchannel :57
PRIVMSG #yourchannel :58
PRIVMSG #yourchannel :59
PRIVMSG #yourchannel :60
PRIVMSG #yourchannel :61
PRIVMSG #yourchannel :62
PRIVMSG #yourchannel :63
PRIVMSG #yourchannel :64
PRIVMSG #yourchannel :65
PRIVMSG #yourchannel :66
PRIVMSG #yourchannel :67
PRIVMSG #yourchannel :68
PRIVMSG #yourchannel :69
PRIVMSG #yourchannel :70
PRIVMSG #yourchannel :71
PRIVMSG #yourchannel :72
PRIVMSG #yourchannel :73
PRIVMSG #yourchannel :74
PRIVMSG #yourchannel :75
PRIVMSG #yourchannel :76
PRIVMSG #yourchannel :77
PRIVMSG #yourchannel :78
PRIVMSG #yourchannel :79
PRIVMSG #yourchannel :80
PRIVMSG #yourchannel :81
PRIVMSG #yourchannel :82
PRIVMSG #yourchannel :83
PRIVMSG #yourchannel :84
PRIVMSG #yourchannel :85
PRIVMSG #yourchannel :86
PRIVMSG #yourchannel :87
PRIVMSG #yourchannel :88
PRIVMSG #yourchannel :89
PRIVMSG #yourchannel :90
PRIVMSG #yourchannel :91
PRIVMSG #yourchannel :92
PRIVMSG #yourchannel :93
PRIVMSG #yourchannel :94
PRIVMSG #yourchannel :95
PRIVMSG #yourchannel :96
PRIVMSG #yourchannel :97
PRIVMSG #yourchannel :98
PRIVMSG #yourchannel :99
PRIVMSG #yourchannel :100
and then:
cat lines.txt | tee /dev/stderr | nc irc.chat.twitch.tv 6667
You will see that all the lines are easily dumped over the TCP connection before the server even responds with the login message, and then slowly but surely 100 USERSTATES will show up as the messages are delivered to chat. You can even terminate the connection (Ctrl+C) while the responses are flowing in and the messages will keep coming in the chat you have opened.
This is the reason why many high-volume bots use connection pooling to send messages over multiple connections.
Point is, there are legit use cases for sending high volumes of messages to chat, especially when you have a verified bot. With only one connection, it is literally not possible to exceed the high 7500 messages per 30 seconds limit, due to this behaviour.
I just want the behaviour to be documented.