Rendering routines with multiple through ports

## Describe the bug
When there's a routine with multiple through ports, it renders very badly, see below:

<img width="181" alt="Image" src="https://github.com/user-attachments/assets/362ab635-f519-4bfd-bdd7-4a0921a36aa6" />

<img width="100" alt="Image" src="https://github.com/user-attachments/assets/da936449-2cf5-4335-9f35-1c6cd346e24f" />