I've seen the app-restart because it ran out off memory, once on the new -15 firmware. The TV had been on for about 5 hours, then we saw some videos YouTube for about 40 minutes, and the the app restarted...
It's sad that you spend money to upgrade a fully functional but outdated TV (Panasonic Plasma with MPG2-tuner), and go for a promissing TV, and choose a model with 1,2 GHz DualCore procesor (you are not told which) and 2 GB RAM, and then end up with a product you can live with instead of enjoy.
A smartphone with these specs greatly outperforms this TV...