Excel for Mac v15.37 on OSX 10.11.6.

Here is a minimally reproducible example:

```
| A | B | C |
|=|=======|========|========|
|1| First | Second | F-S |
|2| 3.4 | 4.0 | =A2-B2 |
|3| 3.6 | 4.2 | =A3-B3 |
|4| 3.5 | 4.1 | =A4-B4 |
```

Sort by `C`

Then by `A`

.

The output is:

```
| A | B | C |
|=|=======|========|========|
|1| First | Second | F-S |
|2| 3.4 | 4.0 | -0.6 |
|3| 3.6 | 4.2 | -0.6 |
|4| 3.5 | 4.1 | -0.6 |
```

The expected output is:

```
| A | B | C |
|=|=======|========|========|
|1| First | Second | F-S |
|2| 3.4 | 4.0 | -0.6 |
|4| 3.5 | 4.1 | -0.6 |
|3| 3.6 | 4.2 | -0.6 |
```

If I copy column C then paste it back in as "values", so the cell contains the literal `-0.6`

rather than the formula, then it sorts just fine. But I don't want to have to do that.

How can I get this to sort correctly?