Every time this poster shows up on trending I think it has something to do with Captain America.

You're not alone. I think the same thing too until I see the name of the show beneath the poster. Someone really needs to change it. As far as I'm concerned this is the poster that is synonymous with this show: http://www.impawards.com/tv/expanse_xlg.html

I simply can't see it as anything other than Captain America's shield.

It's especially bad since you'll probably only see the poster as a thumbnail somewhere, not the big poster to make it clear it's not Captain America.

Glad to see other people are having this problem!