I've reproduced this behaviour in different communities, so it's very likely to be a general problem. I'm using Google Chrome in both Android and Windows 10.
When the question has a big list of tags, we then become able to scroll to the sides as well. Take for example this question
In Windows 10 using Chrome's Toggle device toolbar option in Galaxy S5 (the same happens in other devices like Pixel 2, iPhone X, ...)
In Android using Chrome