Malformed MPI: DEK encoding version 255 not understood

@teythoon: any idea how this error might occur? (This was on Fedora 39 with the OpenSSL backend.)

thread 'sync_decrypt' panicked at tests/gpg-agent.rs:354:67:
called `Result::unwrap()` on an `Err` value: Other(Malformed MPI: DEK encoding version 255 not understood
Stack backtrace:
   0: anyhow::error::<impl core::convert::From<E> for anyhow::Error>::from
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/anyhow-1.0.81/src/error.rs:565:25
   1: <T as core::convert::Into<U>>::into
             at /builddir/build/BUILD/rustc-1.78.0-src/library/core/src/convert/mod.rs:759:9
   2: sequoia_ipc::sexp::Sexp::finish_decryption
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/sequoia-ipc-0.34.1/src/sexp.rs:96:36
   3: sequoia_gpg_agent::gnupg::Agent::decrypt::{{closure}}
             at ./src/gnupg.rs:470:12
   4: tokio::runtime::park::CachedParkThread::block_on::{{closure}}
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/park.rs:281:63
   5: tokio::runtime::coop::with_budget
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/coop.rs:107:5
   6: tokio::runtime::coop::budget
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/coop.rs:73:5
   7: tokio::runtime::park::CachedParkThread::block_on
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/park.rs:281:31
   8: tokio::runtime::context::blocking::BlockingRegionGuard::block_on
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/context/blocking.rs:66:9
   9: tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}}
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/multi_thread/mod.rs:87:13
  10: tokio::runtime::context::runtime::enter_runtime
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/context/runtime.rs:65:16
  11: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/scheduler/multi_thread/mod.rs:86:9
  12: tokio::runtime::runtime::Runtime::block_on
             at ./.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.37.0/src/runtime/runtime.rs:351:45
  13: gpg_agent::decrypt
             at ./tests/gpg-agent.rs:354:9
  14: gpg_agent::sync_decrypt
             at ./tests/gpg-agent.rs:248:5
  15: gpg_agent::sync_decrypt::{{closure}}
             at ./tests/gpg-agent.rs:247:22