Downlinks not working after AWS IoT TTN integration

Hello,
I have been testing the downlink messages from the device console on TTN with and ESP32 board and a RAK2275 Gateway and was fine receiving and sending uplink and downlink messages.
After I deployed the Cloudformation template for AWS integration I started viewing empty payload messages on port 0:

image

I can see the shadow file been created and sync with the uplink messages, but when I try to change the state shadow and send a delta the downlink is not even received by the gateway:

image

The downlink test is not working either.
When I delete the Elastic Beanstalk stack, the downlinks start working again and the empty port 0 messages dissapear.

Have anyone experienced this and do you have a solution?

Thanks in advance