ALB to Nginx every other request fails, doesn't even make it upstream

I have an ALB setup that goes to an EC2 with Nginx within a VPC. Every other request to the ALB will fail with a 504 Gateway Timeout. I've looked into the access logs and it's showing -1 for the request_processing_time, but I've confirmed that the timeouts for my Nginx instance are set correctly. Also, health checks are passing throughout. Moreover, looking at the Nginx logs, and testing via netcat on the EC2 shows that the ALB doesn't even make an attempt to talk to the EC2 on every other attempt. Searching the forums has revealed other people having this problem, yet I've not found anyone that's had some resolve, anyone out there that's successfully troubleshot this?

Edited by: KingOfNuggets on Apr 8, 2020 9:27 AM

Ok, looks like the failing is happening on one specific Network Interface for the ELB. Security groups are the same on both of them, not sure what the issue is, will continue looking.

Edited by: KingOfNuggets on Apr 8, 2020 9:41 AM