`cabal run -O0` seems to use wrong executable

While working on https://github.com/dhall-lang/dhall-haskell, I've run into a weird issue where `cabal run -O0` seems to use an executable that doesn't incorporate the latest source changes. Without the `-O0` flag, `cabal run` behaves as expected.

Is this a known issue?

**System information**

```
$ cabal --version
cabal-install version 3.2.0.0
compiled using version 3.2.0.0 of the Cabal library
```

Start by reproducing the behavior with cabal-install 3.2.0.0 using the dhall-haskell project, comparing `cabal run -O0` with `cabal run` after source changes. Trace which executable each command selects and verify that both commands use the latest source changes.

Written by the indexing model from the issue text.