Thanks for your patience.
Query 1: I was able to reproduce (based on your sample) the issue (see screenshot below)!
please refer the below sample link.
Query 2: I'm facing the exact same issue on my side and i already raised a ticket regarding the same issue but still support team saying that they couldn't reproduce it.
Both are different controls for thread ID 143932 it is related to ej 2 Grid and thread ID 144029 is related to ej 2 TreeGrid. So, please follow that thread ID 144029 for your query.