Linnworks is always sending stock levels from Linnworks to the channel and not vice versa.

If you need to change stock levels on the listing correct way would be to change it in Linnworks and this will be updated to the listing.

If you update it directly on the listing it will be over-written with the details from Linnworks with the next synchronization.

For example

1. TEST_SS7052 in Linnworks has 5 items.

2. Stock level is changed to 10 directly on the Listing.

3. Linnworks will not know about this change and until there will be any stock level change it will not send any update to the channel. 

4. Order placed for SKU TEST_SS7052.

5. Linnworks downloads and saves this order into the system.

6. The stock gets reserved and available quantity decreases in Linnworks.

7. Linnworks sends the new available level to for this SKU to all other channels where this SKU is linked. Because Linnworks was not aware of the change on the listing and in the system, it was 5. One item of 5 available is now sold and the system will send to the channel 4. This will over-write the amount of 9 stated on the channels after the sale.

It is possible to select from which location(s) you would like to update listings. Locations can be same or different for all the channels. More details can be found in this article: Locations-multiple-warehouses