Ecloud: “Connection closed” errors when syncing with Nextcloud macOS client v3.3.4

Nextcloud client: macOS v3.3.4
Operating system and version (eg, Ubuntu 20.04): macOS BigSur 11.6

Hi, I am getting massive errors when Nextcloud client (macOS 3.3.4) is syncing with my account. This used to be smooth without hickups. But when I recently added a few GB locally, it started to flag many individual file syncs with red errors “connection closed”.
Anyone has an idea what the root cause might be? Thanks.

Debug log snippet:
2021-09-28 09:59:46:238 [ warning nextcloud.sync.propagator ]: Could not complete propagation of “<filename.pdf>” by OCC::PropagateUploadFileNG(0x600003e37180) with status OCC::SyncFileItem::NormalError and error: “Connection closed”

This has been solved with the upgrade to macOS client 3.3.5 it seems.