Hello
In recent versions you added a function that kept the search in the backend better. Not sure if this is related to the issue but seems so.
To replicate:
1- Search for a customer name in the orders or customer tab in vm backend,
2 -Click in the customer username and then in the tab "order list".
If other customers appear in the search result the "order list" gets mixed up with orders from other customers.
Another easy check is to search for a concrete order number.
Then click in the username and "order list" will only show that concrete order.
vm 3.0.14 joomla 3.5.1
I tested in Chrome, Opera and Firefox with same result.