I’m running into the same issue. Text-only posts work fine, but if there’s an image in the post, I get the same “no implicit conversion of Array into String” error.
From the error message, it seems like something in the image data is confusing the plugin or Gemini. Maybe it’s sending the image info in a way that the API doesn’t expect.
Good to know it only happens with certain bots. Hopefully, this gets sorted out soon.