When automatic PLL management mode is enabled on the U4 series AVR8 chips, the PLL is now configured for 48MHz and not a divided 96MHz, to lower power consumption and to keep the system within the datasheet specs for 3.3V operation (thanks to Scott Vitale).

LUFA/Drivers/USB/Core/AVR8/USBController_AVR8.c

@@ -68,7 +68,7 @@ void USB_Init(
 	if (!(USB_Options & USB_OPT_MANUAL_PLL))
 	{
 		#if defined(USB_SERIES_4_AVR)
-		PLLFRQ = ((1 << PLLUSB) | (1 << PDIV3) | (1 << PDIV1));
+		PLLFRQ = (1 << PDIV2);
 		#endif
 	}
 

LUFA/ManPages/ChangeLog.txt

@@ -15,7 +15,8 @@
   *
   *  <b>Changed:</b>
   *  - Core:
-  *   - None
+  *   - When automatic PLL management mode is enabled on the U4 series AVR8 chips, the PLL is now configured for 48MHz and not
+  *     a divided 96MHz, to lower power consumption and to keep the system within the datasheet specs for 3.3V operation (thanks to Scott Vitale)
   *  - Library Applications:
   *   - None
   *