Instability issues have been observed on newer Galaxy devices, Pixel models, Droid Z and the OnePlus running Android OS 8 (Oreo).
There is currently no update to resolve those issues but you can send your proof of purchase to our support team for a full refund. Also, include a screenshot of your About this Device screen when you submit a ticket so we can add more details to our existing bug database.
Unfortunately, we are unable to process refunds for orders placed over a year ago. Follow this article for alerts when more info is added to it.