[Bug]: Concurrent requests resulting empty list

no error logs, some possibilities:

- aiohttp client cannot handle multiple requests at the same time.
- host provider limit http requests of the app.
- some invalid encoding in the requested page makes parsing function raise exception.

solution from chatgpt:

🔍 What Might Be Going Wrong
You're passing a base URL (YURAMANGA_URL.geturl()) to aiohttp.ClientSession(...)
This is not valid — aiohttp.ClientSession() doesn't accept a base URL as a positional argument like that.

🔧 Fix:
Make sure you're not doing this:

# ❌ This is incorrect usage
```python
aiohttp.ClientSession(YURAMANGA_URL.geturl())
```

# ✅ Correct usage
```python
aiohttp.ClientSession() # no URL here
```

Then later:

```python
await session.get(YURAMANGA_URL.joinpath("some/endpoint").geturl())
```

Or construct the full URL manually in your routes.

Start by reproducing the concurrent-request case and inspect the aiohttp.ClientSession usage described in the issue. Check whether requests fail during fetching or parsing, then verify that concurrent requests return the expected list and that failures are logged rather than silently producing an empty result.

Written by the indexing model from the issue text.