I am getting this as well in 4.18. Supposedly I see in the ticket, this is a target fix for 4.20… I mean, this is stuff that shouldn’t be broken in UE4 in 2018. The rest of OSS and especially OSS Steam should be 100% good to go. But we are still waiting on things like this: Advanced Sessions Plugin - Community Content, Tools and Tutorials - Unreal Engine Forums to be fully implemented into the engine by default… or even full wrapper like UWorks but with actual OSS support.
I know Epic doesn’t have any plan on putting games on Steam, so it may not be High Priority for Epic, but I would guess that at least 90% of your userbase WILL be using Steam.