Connectors vanish in certain positions
#### Summary:
When connected objects overlap, there are some angles where their connectors are not visible (also don't seem to be below the objects, as far as I could see).
#### Steps to reproduce:
Video (unnecessary long):

#### What happened?
Connectors aren't always rendered.
#### What should have happened?
Connectors should always be rendered.
Note: the Connectors feature is supposed to be refactored into an LPE. It would still be nice if this case were tested with the upcoming LPE, too.
#### Version Info:
```
- Inkscape Version: 1.1rc
- Operating System: Linux Mint 20.1
```
issue