If you make the first page gather: existing, and for example the third page gather: all, then all new items will be moved to page 1. As I understand it, items that are not yet in the backpack should be moved to page 3 where gather: all.
and craft doesn't work. retrieve: on
if I want to move, for example, an ax from the inventory to a cell on the belt that already contains, for example, a bow, that is, swap them, then the bow is removed and the ax is moved to the backpack if gather: all is enabled
also when splitting a stack, a part flies into a backpack

Thank you for testing the beta and providing this feedback!

If you make the first page gather: existing, and for example the third page gather: all, then all new items will be moved to page 1.

Thanks for reporting. I have released a fix for multiple gather-related issues. Please redownload v3.10.

and craft doesn't work. retrieve: on

You are probably experiencing a plugin conflict between Item Retriever and another plugin, especially if other operations such as building and reloading are successfully taking items from the backpack. Please search the code of your plugins for "CanCraft" to determine which plugins might be conflicting, then try unloading those plugins to narrow it down further. I will be working more on Item Retriever to create a resolution path for such conflicts, but changes will most likely be required in whichever plugin is conflicting.

if I want to move, for example, an ax from the inventory to a cell on the belt that already contains, for example, a bow, that is, swap them, then the bow is removed and the ax is moved to the backpack if gather: all is enabled

Thanks for reporting. I have released an experimental revision of v3-10 that should mitigate this issue (click here to download). Currently, gather mode will detect when an item is removed, and remember the item and the frame in which it was removed, in order to prevent gathering it in the same frame. However, when swapping an item between the belt and main inventory, technically two items get removed before either of them is added, so the plugin forgets about one and ends up gathering it. This experimental version simplifies the logic to just pause gather mode for one frame whenever an item is removed from the player inventory. That will also work, for the case where you are swapping an item between your inventory and one in another container.

also when splitting a stack, a part flies into a backpack

This is a known limitation which will be documented. This cannot be fixed at this time because there is no feasible way to detect that the item that was created from the split operation came from the player inventory. The only possible ways today would cause significant performance loss and/or high possibility of plugin conflicts.

evgeny

and craft doesn't work. retrieve: on

guilty XPerience

Thanks for confirming. Another user reported that issue with XPerience. I started a conversation with the dev last week and we have a path forward. I'll work more on it tomorrow.

also when splitting a stack, a part flies into a backpack

One solution I'm thinking about for this is to prevent gathering any item that matches an existing stack in your inventory. For example, when a new stack of scrap enters your inventory, if there's another stack of scrap, the new stack will not be gathered. Another thing I may explore longer term would be to add some sort of button that you can click on to undo the last gather event.