That’s probably the result of Jerboa detecting that the link is to a Lemmy community and handling it gracefully. While that’s a great feature the Jerboa devs have included, it’s not how Lemmy currently functions with regard to linking to communities. Lots of apps and browsers don’t handle the URLs nicely, unfortunately.
Lemmy devs should probably implement something to natively handle URLs and “properly formatted” links in the same way. If Jerboa can do it, then it can obviously be done. Until then though, proper formatting helps unite Lemmy users across platforms.
TLDR: I get on a soapbox about cross-platform interoperability because I had a bad week at work.