Edit: to lemmy users, this link looks no different. To third party app users and Kbin users, etc, the previous links all cut out after the first underscore.
I mean sure, but that's a bit more involved than just pasting a link with no code and having the renderer make a link, which lemmy is supposed to do. The app is failing to meet the lemmy spec, the developer should fix that.
So, it's actually more a Lemmy bug. Lemmy stores the comments just fine but the API displays it with markdown. The double underscore is screwing up other apps abilities to display it and there's really no way to avoid that. A third party app can't tell if it's supposed to be interpreted or not.
So on Lemmy, all the URLs look fine. On Kbin or any other apps, they'll all get cut off after the first underscore.
How? I read the comments and I can't replicate the issue you are experiencing. The original link is causing the problem for me (but I can still access the page).