Even the most hardcore OnePlus fan will admit the built-in camera app kind of sucks. It doesn’t matter how good the camera hardware is if the software managing it sucks.
Historically, the OnePlus has many problems with it’s camera. With the OnePlus 3T the most common problem is the focus. Not just auto-focus but even manual tap to focus. It’s often just out of focus and even when it does find the sweet spot, it doesn’t hold it long before deciding to re-focus somewhere else.
Aside from the focus issues, when shooting video on the front camera, the audio is nearly always out of sync with the video. Although that doesn’t matter too much because the audio is so poor that you usually can’t use it anyway.
Twitter released an updated interface/design to their website and their apps. The camera is now lightning fast and amazingly performs much better than the official OnePlus camera application!