Unfortunately, the issue is iCloud. When you leave a Logseq graph open on multiple devices at the same time and use iCloud to sync between them, you’ll for sure get sync conflicts. Luckily, Logseq creates backups in the /logseq/bak folder that’s within your graph folder.
The solution is to only have Logseq open on one device at the time, to use Git for syncing, or become a Logseq Sponsor so you get access to the alpha version of Logseq Sync.