Bot doesn't see the server responses to its slash commands?

I’m sending the commands as PRIVMSGs as described in the documentation:

Chat & Chatbots | Twitch Developers : Twitch slash commands are sent via PRIVMSG . The following table lists these commands and required scopes…

So in the code, the commands are sent just like any other message the bot sends.

        if (twitchChatMessage.Message.StartsWith("?slash",StringComparison.OrdinalIgnoreCase))
        {
            await _twitchBot.SendMessage("Sending slash / dot . commands: /vips .vips /mods .mods");
            await _twitchBot.SendMessage("/vips");
            await _twitchBot.SendMessage(".vips");
            await _twitchBot.SendMessage("/mods");
            await _twitchBot.SendMessage(".mods");
            await _twitchBot.SendMessage("Commands sent.");
        }

The above messages are formatted in SendMessage:

    public async Task SendMessage(string message, string channel=chatChannel)
    {
        await TryWriteLineAsync($"PRIVMSG #{channel} :{message}");
    }

And sent with the streamWriter:

            Console.WriteLine($"<{line}");
            try
            { 
                await streamWriter.WriteLineAsync(line);
                //throw(new Exception("Some f'cking thing in TryWriteLineAsync"));
            }
            catch (Exception ex)
            {

                Console.WriteLine("TwitchBot Exception! in TryWriteLineAsync", "red");
            ...

I’ve added those messages/commands to be sent when it joins, and also set a ?slash command to send them later just in case there was some race condition or whatever sending them too fast on connect. In both cases, the messages before/after the commands do show up in the chat for others to see - but the commands are not echoed, nor is their response seen by the bot on its streamReader.

So here’s what the console output looks like showing all the messages that are send/read on the streams:

And here’s what it looks like on the chat output:
Bot_Cmds_Chat_01

I’ll try adding the capabilities requests now and see if that changes anything.