If its the same problem on two phones it could be a application, or your backup is corrupt. If you haven't already do a backup and reload of the operating system without doing a restore. Setup your phone from scratch. If the led light issue isn't present you can restore your backup on the phone and if issue continues its your backup. When testing phone install each app you had one at a time to see if the issue starts after downloading a particular app. Best to give 5-10 min between app installs to test.