It's possible that the API has issues but the web front-end doesn't. If Connect works otherwise fine with other instances, it's 100% buy the app at fault.
Meta
Yhteisö instanssia koskeville tiedotuksille, palautteelle, metakeskustelulle ja avulle. Katso myös UKK!
Community for announcements regarding the instance, feedback, meta discussion and help. Check the FAQ also!
Users needing support can also come to our Matrix Space.
Tukea tarvitsevat käyttäjät voivat myös tulla Matrix-tilaamme.
Does API stand for apple pie Information?
Bone apple pie information
What do you mean by your last sentence? I don't use my second account on other instance much so I don't know if there's often similar problems in other instances. I use Sopuli most of the time.
Can’t speak for Connect specifically but some Lemmy clients glitch out like that when the login expires and you have to re-add the account.
On Android, clearing the app cache or even data after an upgrade has been said to stop that happening. Until the next upgrade.