Same as FB24740548 and FB24924733: iPhone Handoff adverts carry SFActivityAdvertiserOptionFlagCopyPasteKey = 0 after a copy. The Mac receives them and fetches Handoff payloads with error=(null), Mac-to-iPhone clipboard works, ClipboardSharingEnabled = 1 on the Mac, and toggling Handoff, Bluetooth, Wi-Fi or Airplane mode doesn't help; only an iPhone restart clears it.

Same for me - FB24985155