[2.0.28] -ve Platform Request when hub contents change

[Khazul]

Observed behaviour

When a platform has a logistics request that is over-satisfied, for example a request for 100 fusion cells and there are 138 on board and the contents of the hub change (for example items added or removed via inserters), then the excess amount (38) in this case can be observed as an intermittent -ve request on a planet silo with 'read requests' signal connected and selected.

Expected behaviour

Excess amounts on platforms should be ignored and a platform should not be able to cause a -ve request on a silo as this will sum with and interfere with other requests for the same item.

Additional Observation

This only seem to apply when hub content are changing. When the hub contents are static, then this does not occur even though there may be an excess of a requested item which is as it should be. I suspect the intermittent -ve request is actually only for a single tick around platform hub content changes and goes away when a previous tick value and current tick value in underlying (C++?) code are the same. The contents change in hub *may* need used slots to change (ie stacked added or removed), not just a few items added or removed. I am not 100% sure of the need for slots to change however.

[Loewchen]

Post the save file and a screenshot of what you consider the issue please, see 3638.