Problem with scheduled item synchronization

I have a strange problem with syncing scheduled item.
I had a scheduled item and I deleted it on my Windows laptop. Then synced. I did this some time ago.
Yesterday I opened Everdo on Macbook which wasn’t synced for a longer time. After sync, this scheduled item wasn’t deleted from Macbook. It is still there. On Windows and moble, now I have this item on my Focus list but it doesn’t appear on the Scheduled list.
It looks like the Scheduled list wasn’t synced properly.

Here is what I think happened.

When you opened Everdo on your Mac, looks like it created a copy of the scheduled item before sync ran. After sync finished, the original scheduled item was removed, as it should, but the copy remained (these two are independent). Then the copy was synced to your other devices.
Does this sound consistent with your observations?

Normally the app tries to run sync before processing scheduled items, but sometimes sync is delayed and the scheduling runs first, leading to this situation.

Not exactly, because on my MacBook the original item still exists on my Scheduled list. On other devices there is only a copy.

This one item still exists on MacBook but it doesn’t sync with any other device. Any ideas?

First I would try to modify the item, so that it gets picked up by the algorithm for next sync. It if still doesn’t sync, it might be easiest to re-create.

It hasn’t synced even when was edited.
This particular item is not a problem but the question is what has happened?

I understand. Unfortunately so far the cause is unclear. I’m sure it’s related to the deletion of the item.