import of private key from Flamingo NOSTR browser extension fails with "private key not recognized" message

[sysfu]

Trying to import my Flamingo private nsec key but it's failing with "private key not recognized" message.

Console output

Environment is PureOS 11 Crimson (debian based)

$ gossip
Gossip 0.11.3
2024-10-02T20:59:52.931755Z  INFO gossip-lib/src/filter.rs:30: No spam filter: No such file or directory (os error 2)
2024-10-02T20:59:52.936321Z  INFO /usr/local/cargo/git/checkouts/egui-904381843a0f3282/63dde4c/crates/eframe/src/lib.rs:255: Both the glow and wgpu renderers are available. Using glow.    
2024-10-02T20:59:52.989049Z  INFO /usr/local/cargo/registry/src/index.crates.io-6f17d22bba15001f/winit-0.29.15/src/platform_impl/linux/x11/window.rs:189: Guessed window scale factor: 1