That’s a really weird bug. It reminds me of Protonmail: All emails disappear from inbox (and reappear, then disappear again...) … but that’s Prontonmail, and this is iCloud? Hm.
Are the emails actually being removed from your inbox folder (it would show up as such in the iCloud web client), or does Mailspring just act like that’s the case?
Has anyone else seen this happen?