Thumbs down SW 2 Bluetooth Problem?

Hi,
I've got yesterday sw2. It is really cool, but sometimes i have problem with bluetooth. Sw2 seems to be connected with phone, but when i start some app, it is loading, but this app don't start. I must restart my watch and then everything works fine, but then when i don't use it for a while it didn't want start against. I am using nexus 5 with custom rom. Where can be a problem?