I'm not familiar with the details of AWS here, but maybe the OP means mapping two different host ports to the same port on two different containers? That's all I can imagine that would be a container antipattern in the way described.
That is perfectly possible with ECS, so I don't know what OP was referring to. The thing I remember though is that you have to jump through a lot of hoops like making 4 APIs calls (or worse with pagination) for what should have been a single call to make such a system work on ECS.
