It’s still drawing power.
Also dump1090 will after some time be restart by piaware.
If you really want to test if power is the problem it’s probably best to remove the 2nd dongle for 1090 MHz.
Most likely it’s a power issue.
Solutions:
- other power supply (for example "official RPi power supply)
- powered USB hub to connect the dongles
Also if you want to get back your old id:
For Beginners - How to Get Back Existing Station Number in A Fresh Install