Looks like we can't reproduce the issue or there's a problem in the test case provided.
B2: Store setClearOnPageLoad property not functioning
The store.setClearOnPageLoad(false) has no effect when using store.load(). Multiple store.load() calls overwrite any existing records.
Is this fixed in B3?
The store.setClearOnPageLoad method only handles the loadPage, nextPage, previousPage methods. Currently there is no configuration method on the Store that handles all load calls (something like clearOnLoad). The way you can currently have the records be added is by passing addRecords: true to the options of your load call.
We might add a nicer configuration for this in a future release.
This works great! Please add this to the store documentation and please include a reference to this in the clearOnPageLoad store configuration documentation.