Originally posted by Khaos:

I can confirm a similar issue. Sometimes the extractor is 0/10 even after waiting a few days. But, after I get in the area it starts up again - if I port out and check back on it later it will have sap. This doesn't always happen - so to me it looks like a bug. This is true for the server we run, but on my local seed this is not happening, yet. May be coincidental - but my gut tells me there is a bug here.

I don't think it's a bug but more of a secondary effect of the way the game prioritises elements of the surrunding areas or recently visited areas.
Similar to minecraft, the game runs on seeds, and "chunks".
Maybe the game is designed to prioritise chunks of the map the player regularly visits and reduces the priority of the ones the player never goes to, adding to that the most recent chunks the player visited.

Lets say i always visit the same 5 chunks, but then i go on exploration, the game will remember those 5 chunk and may still consider making my boars reproduce, but if i stop going there for 3h and i visited 40 additionnal chunk, teleported back to my 4 other most visited ones but not the fifth one for a long time, then the game may put it in low priority and then the sap will not accumulate in the extractor.

I am only speculating here, but if i was a game designer given a project like valheim i would most likely try to optimise the game like that or in a similar way of giving priorities to some limited numbers of chunk of the map at the same time to avoid overloading the RAM