@pkks297 try upgrading to the latest firmware. https://static.tp-link.com/upload/firmware/2025/202505/20250528/ER605(UN)_V2.0_2.3.0%20Build%2020250428.zip then enable ARP Detection on LAN interface

@TheNetAssistanc Have you disabled SIP ALG ?

@drigo I don't know if it matters but 74.162.40.0/24 is a public ip pool, you should change it to a private ip pool, That could be the problem.

@drigo here is a guide on how to disable NAT https://community.tp-link.com/en/business/forum/topic/770860

@Julian2111 No, I don't have any more suggestions, I haven't had the same problem, so you'll just have to test and see if it happens again in the new site. I also use it a lot VPN, have OpenVPN...

@SebastianH Switch ACL is not stateful, try enabling bidirectional ACL rules