@evb it's for doing a gasmeter, counting with a reed sensor.
But for my tests, the read sensor is not connected. So nothing wakeup the interrupt.
I just send every 10 minutes the counter, as a keepalive. (Domoticz don't put the sensors as "red" )
First, I was doing test with newbie pcb, and I had strange values.
So I remove everything, and I do test with breadboard and dupont cable.
I just have the arduino pro mini, and the rfm69 solder on a nrf2rfm69 board and a 0.1uF capacitor.
I have 2AA alkaline battery, connected to the VCC/GND pin of arduino and to 3.3V/GND of NRF2RFM adapter.
I measure the current on the cable between battery + and 3,3V of NRF2RFM69 (like in your photo)
I have no scope, so I can't check NSS/MOSI/... and so on. But the transmissions are OK, and everything is working well, except current when sleeping.
I had no time today to do more test today. I will double check everything as soon as possible, try your sketch