Can anyone explain what it means?
Based on what I can get from the source code:
The client keeps a snapshot of the server status locally.
This snapshot needs to be updated all the time (frequency depends on the 'snaps' variable)
To save bandwidth the game only transfers changes from the last snapshot it thinks the client has. (Delta snapshots)
If the client for some reason cannot construct the new snapshot based on the old snapshot+delta snapshot it will give an error (as the one in the screenshot) and request a full snapshot from the server to get back in sync.
This is how I understand it but I don't truly understand the code only the comments in it.
Reducing the snaps variable temporarily might help the game get back into sync. The message suggest that a data package was dropped and the game cannot construct the new snapshot. The code suggest that it is caused be a too big delta package but I don't understand why the server would send such a thing.