I've had a few system crashes, they look like a restart but only last a few seconds. And afterwards I've had issues with things getting weird, so if you have one do this:
1. Go to Samsung Members app (so it can catch the crash and do its automatic error report.
2. Wait for the report to finish sending.
3. Trigger a manual reboot.
4. Clear the system cache.
+ Power off the phone.
+ Hold power and volume up button down until you reach the debug menu
+ Use volume buttons to choose, and power button to select 'Wipe Cache Partition' then select 'Yes'
5. Repair Apps.
+ In the debug menu from step 4, use volume buttons to choose, and power button to select 'Repair Apps'
You will have a much more stable experience doing this than letting it cascade crash after crash.