+1 for Raindrop, that app is amazing, I keep watching for a self-hosted version/alternative that is as good and they are getting closer. The killer feature for me is being able to highlight stuff and then when you visit the site again you see what you have highlighted (in addition to saving them elsewhere). I also pay for premium because it’s great, I don’t use a ton of the pro features either.
I know you solved it but for anyone that finds this later this feature/behavior is typically called “NAT Hairpin” in case you are looking for a setting to enable or disable, hope this helps!