expand/collapse arrows disappear between filter states


I am experiencing an issue with the DHTMLX tree grid where the expand/collapse arrows (icons) disappear when I switch between filter states. In the first filter state (state1), the nodes (whose arrows disappear) have children, but in the second filter state (state2), they do not. The arrows disappear when switching from filter state2 to state1. The arrows reappear (in filter state1), only after clicking on the node in question (which expands the node and displays its children). Can anyone explain what is going on here? Is this a known problem with the treegrid? Is there a work around for this issue?

Some additional notes:

  1. our tree grid data is loaded via JSON
  2. we are using smart rendering

Unfortunately we cannot reproduce this issue locally. Please provide us any kind of sample or a demo link so we can reproduce an error.