Build 10080 of Windows 10 Mobile is a bit rough, and has resulted in many windows phones being hard reset.
Microsoft is of course working on a new version which will hopefully be an improvement, but it seems unfortunately we will have to wait a bit more, as the build Microsoft was hoping to release appears to have a bug.
Read: Windows 10 Mobile Build 10080
The lock screen bug means that Microsoft is moving onto testing a new build, which will presumably have a bit more polish and new features, but will probably mean a few more weeks of testing.so it looks like we have to wait for latest preview.