Unable to airdrop from Noteful

Unable to airdrop PDF files from the Share button in Noteful, or Noteful-exported PDFs from the Files app. "Airdrop failed" in macOS/ iPad OS. Airdrop is sent to "All" on receiver. I am on a university network and signed in with the same Apple account to the devices. For comparison, I am able to airdrop from Notes app. (Sharing an "image" in Noteful (and airdropping) works, but is cumbersome since it makes an image per page.)

Noteful 1.4.34, Build 198. IpadOS 26.2.1, macOS 15.7.3.