It may be an issue of ConvertKit just connecting to your Teachable account as a whole and not to the individual courses to tag customers from each one. Have you created a separate tag and automation rule for each course as seen in here: https://support.teachable.com/hc/en-us/articles/219826907-ConvertKit-and-Teachable178
TC Headley
Brand Strategist, Divi Designer, Mac & Cheese Connoisseur