As seen in the video below, posted by Reddit user 3DTbrandonl, players are able to snipe through stairs that have been built:
[iframe src=’https://gfycat.com/ifr/WhoppingScaryBlacknorwegianelkhound’ scrolling=’no’ width=’1′ height=’300′ allowfullscreen>]
This is an issue that Epic are aware of and will be fixed in next weeks update when V.3.6.0 is released, as stated by Epic employee MrPopo: