Your description matches what could happen with the buffer bug. Regarding the App crashing: hardening it against garbage data is on my list. It happened also with the buffer bug on the Twizy, because the data parser is a bit too strict.
Btw: I've been in contact with an enthusiastic Leaf owner named Slava from the Ukraine, told him to get in contact with you. He thinks about setting up an OVMS server for his region. As you may have guessed, there is no NissanConnect in the Ukraine... ;)