Running Appium 1.7.0 in simultaneous is stops the first session


I ran Appium 1.7.0 simultaneous (2 Android devices) , I have 2 Android devices connected,
and I start a test without sending udid capability.
The first test (Without udid) - catch the first device that shows on adb devices, while it’s running I start my second test (also without mention udid) , I expect it to take the second device on adb devices list (the one that truly available) but it taking the first one at the middle of the run.
so my first test was failed, and the second ends successfully.

if I mention udid, it’s success to run simultaneous, but without udid it’s not working.

There is an open issue to fix it ?