The case you are describing is becoming very trendy with OTOs recently, as many fall into the trap of using #yes-link-multi instead of the support #yes-link, as described in this thread: Funnelish - OTO #yes-link-multi Not Working
Can you please check that thread, and see if it’s the same case as yours and if the solution provided there solves your issue, will be around to assist you further as needed