If tests are numbered 10, 20, and 30, then the .results file looks something like

10
:sortFull ....
[
...,
...,
...
]

20
:sortFull ....
[
...,
...,
...
]

30
:sortFull ....
[
...,
...,
...
]

However, if the .actual file is missing a test (e.g. test #20) due to an execution error (e.g. an operator is no longer supported), then it'll look like

10
:sortFull ....
[
...,
...,
...
]

30
:sortFull ....
[
...,
...,
...
]

Hunk headers will pick up the "latest test number" as 10, when the actual error is in test 20 (by the absence of its results).

If possible, we should try to make this messaging clearer by detecting this situation and correctly indicating that test 20 is missing, rather than referencing the previous test.