Incoming webhook puts messages in conversation between two users instead bot-to-user

Hello, I couldn’t find similar topic - if there’s one, I will be grateful for link.

Summary
Text sent from Zapier to Matermost via incoming webhook is showing up in private conversation between me and another user, instead of conversation between bot and user.

I have an issue with incoming webhook - note that I am a newbie to Zapier, webhooks and so on, so part of the stuff I do is just trial-and-error.

I have following incoming webhook set:

which - obviously, looking at the title :wink: - I use in Zapier in Zaps like this:

Now what’s the catch - my intention would be for the incoming message to be sent directly to the person, who did the Zap’s trigger.
But when I put @User name in “channel” like this:

The message is not sent from mib_bot to user in their private conversation, but instead, it is sent by mib_bot between me and the user. (Yes, I am aware that on the screenshot the user is ME, but of course if the user is ie. weramarek, the described thing will happen).