The new 1.13.0 version of the canvas exhibits an issue where, in themes such as AnuPpuccin and Shiba Inu, the connections between nodes are not visible.
All looks fine using the default theme:
For bug reports, you need to follow and include the bug report template, so I’ll move this to Help.
AnuPpuccin and Shiba Inu both haven’t been updated in a while; they likely need one. A css snippet may be able to fix the issue if you want to continue using those themes.