There are more messages than just the presentation messages that don't show in the HA logs, like find parent. You should check the actual GW debug output when this situation occurs to see them. This would be really necessary if you ask me, otherwise it can't be seen what happens to the gw to make it hang.

V_VARx not working because HA saves states/data from mysensors to file. When you update sensor data from HA that file doesn't change. I can send data to node by V_TEXT messages using notify service. It works :)