specific user download fails after two pages (99 posts)

## Library version

```
instalooter 2.4.4,
```
also tried a version installed with `pip install --user instalooter --pre`

## Environment

Two machines on entirely different networks.

Machine 1
* *MacOS 10.15.7 (Catalina)*
* *Python 3.9.5*

Machine 2
* *Gentoo Base System release 2.7*
* *Python 3.8.9*

## Error description - runtime

### Reproducible test case

```
instalooter user cista__dusa
```

### Expected behaviour

Downloads all photos (over 900).

### Actual behaviour

When downloading the specified user, the downloading stops after 2 pages. The page iterator disappears and then the application finishes without any error, even with `--traceback -l DEBUG` set.

```
>>> instalooter user cista__dusa --traceback -l DEBUG
2021-05-22 22:39:30 *domain* instalooter.cli[93949] DEBUG Opening destination filesystem
2021-05-22 22:39:30 *domain* instalooter.cli[93949] NOTICE Starting download of `cista__dusa`
2021-05-22 22:39:41 *domain* instalooter.cli[93949] SUCCESS Downloaded 99 posts.
2021-05-22 22:39:41 *domain* instalooter.cli[93949] DEBUG Closing destination filesystem
```

## Notes

I also tried deleting `~/Library/Caches/instalooter` and logging in. Did not succeed.