Thank you for confirming! Please send a private message with your model code and IMEI number. If this occurs in Safe Mode and with multiple chargers, your phone may need repairs. http://bit.ly/2XERsky
Fast charging was enabled, so that wasn't the issue. I rebooted my phone and turned fast charging on and off (just to be sure), waited a few hours, and now it works just fine. Still not sure what the problem was, but it appears to be resolved. Thanks all for the helpful comments!