Looks like you found a bug!
panic: interface conversion: upstream.Entry is nil, not *upstream.Object
goroutine 4004 [running]:
github.com/rclone/rclone/backend/union.(*Object).Update(0xc0008c74d0, {0x24986f8?, 0xc000b020f0}, {0x2482c00, 0xc00053d400}, {0x7fdc7e341750?, 0xc000aba300}, {0xc0007b2f90, 0x1, 0x1})
github.com/rclone/rclone/backend/union/entry.go:76 +0x59c
github.com/rclone/rclone/fs/operations.Copy({0x24986f8, 0xc000b020f0}, {0x24ab7c0, 0xc0002233b0}, {0x24ab830?, 0xc0008c74d0?}, {0xc000c1a0a8, 0x15}, {0x24aa5d0, 0xc000aba300})
github.com/rclone/rclone/fs/operations/operations.go:437 +0x1bea
github.com/rclone/rclone/fs/sync.(*syncCopyMove).pairCopyOrMove(0xc0007ceb40, {0x24986f8, 0xc000b020f0}, 0xc000253778?, {0x24ab7c0, 0xc0002233b0}, 0x76f986?, 0xc000d62ea0?)
github.com/rclone/rclone/fs/sync/sync.go:437 +0x20a
created by github.com/rclone/rclone/fs/sync.(*syncCopyMove).startTransfers
github.com/rclone/rclone/fs/sync/sync.go:464 +0x45
I can't immediately see a fix for this so I'm going to need to be able to reproduce the bug.
Can you try simplifying the config down so you can still reproduce this bug with the smallest possible config?
Thanks