Panic in setup_outline_page_ids()

[asdfuser]

Calling get_toc() on the following pdf causes a panic in setup_outline_page_ids:
https://www.etsi.org/deliver/etsi_ts/102000_102099/102034/01.02.01_60/ts_102034v010201p.pdf

The application panicked (crashed).                                                                                                                                                           Message:  called `Result::unwrap()` on an `Err` value: Type                                                                                                                                   
Location: /home/daniel/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lopdf-0.32.0/src/toc.rs:71                                                                                                                                                                                                                                                                                      
  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━                                                                                                                                            ⋮ 9 frames hidden ⋮                               
  10: core::result::Result::unwrap::h1dd6925ad870affb                                                                                                                                    
      at /rustc/07dca489ac2d933c78d3c5158e3f43beefeb02ce/library/core/src/result.rs:1073
  11: lopdf::toc::setup_outline_page_ids::h8d4e621112de3625                                                                                                                                   
      at /home/daniel/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lopdf-0.32.0/src/toc.rs:71
  12: lopdf::toc::::get_toc::h2f5fa8a1257fe404                                                                                                                
      at /home/daniel/.caThe application panicked (crashed).                                                                                                                                                           Message:  called `Result::unwrap()` on an `Err` value: Type                                                                                                                                   
Location: /home/daniel/.cargo/registry/src/index.crates.io-6f17d22bba15001f/lopdf-0.32.0/src/toc.rs:71                                                                                                                                                                                                                                                                                      
  ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ BACKTRACE ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━                                                                                                                                            ⋮ 9 frames hidden ⋮                               
rgo/registry/src/index.crates.io-6f17d22bba15001f/lopdf-0.32.0/src/toc.rs:99
  13: getsi::pdf::lopdf::get_toc::h528e8dc44864dd4d                                                                                                                                           
      at /home/daniel/scm/osmo/rust/getsi/src/pdf/lopdf.rs:7       

Opening the file in evince shows that some chapters are missing pages (4 and 4.1) in the index view.
It looks like the second unwrap in the line fails and destination.page().unwrap().as_reference() returns an error