Aggregation not updated in tree when using filters

Hello,

When using a tree view with filtering enabled and aggregation on a column, the result of the aggregation is not updated when we filter the rows.

This example is forked from the sample 319 Complex Trees, with a COUNT aggregation on the name level. If we filter for example on the age column, the count is never updated Plunkr

Calling refresh() on gridApi does not update the value either, the only way to have the count updated is to rebuild the data, but then all rows are collapsed

In this example, click on the rebuild data button after filtering and the count is updated Plunkr 2

Is this beahviour expected ?