When using the magnet upgrade of Sophisticated Backpack items picked up by the magnet are not shown by Pick Up Notifier - not sure which mods need to add compatibility support to allow this to work.

Version:
Minecraft: 1.16.4
Forge: 35.1.13
PickUpNotifier-v1.2-1.16.3
sophisticatedbackpacks-1.16.4-1.0.0.94

Added something for this in the 1.17 version of Pick Up Notifier. You'll have to enable the Backpack Compatibility config option once Sophisticated Backpacks updates.

I'd like this too, it'd be awesome!

I'll also comment this on Sophisticated Backpacks' page in case it's something that can only be fixed on their end.