Did you create the node fresh, or copy it from the other trigger? If you copied it, it will have the same webhook endpoint (UUID), so they’ll both try to register the same URL. You can check by expanding the Webhook URLs
To avoid this you can create a new trigger instead of copying the existing node, this will generate you a new unique URL that won’t clash.
If you’re so inclined you can also change one of the existing triggers by copying the node into a text editor, and changing the webhook ID, in this case I’ve changed webhookId from the generated 2cf3b520-e9a1-4c69-98b8-84752a519a12 to telegram_channel_post: