Something that used to work in VM2, but doesn't in our current version 3 of VM.
When trying to update an order status, by wanting to add a comment only (and not changing the status), the status does not save, and the comment is lost.
The order status updates only when the new status is different than the previously saved one.
(It may be solved in a slightly newer version of VM3, we plan our updates on every couple of months)
[J3.8.10/VM3.2.15]
This was discussed here very recently ..
http://forum.virtuemart.net/index.php?topic=141529.msg498676#msg498676