Fingerprint recognition

For some strange reason my phone won’t recognise my fingerprint after approx 7pm. I don’t have any issues during the day. It’s not saying that it can’t recognise it like it does if there’s dirt on the home button or my fingers wet, the fingerprint logo just sits on the screen like I havnt even put my finger on the home screen. I have only had my phone for just under 17 weeks and this has been an issue for a while. I have an appointment at a stormfront shop for them to take a look but it states on their website that software issues (which this sounds like) are not covered under the warranty. Anyone know where I stand please