Mediaplayer-app doesn't pause if lock the phone right after launching it

[TarotChen]

Test Environment:
$ system-image-cli -i
current build number: 40
device name: krillin
channel: ubuntu-touch/rc/bq-aquaris.en
last update: 2016-01-19 02:38:56
version version: 40
version ubuntu: 20160118
version tag: OTA-9-rc
version device: 20160108-efc96d8
version custom: 20160111-926-36--vivid

Steps:
1.Play a video from the video scope
2.While mediaplayer-app is loading, press the power button
3.Wait a while and check
4.Unlock the screen, going back to mediaplayer-app

Actual result:
Meidaplayer-app continues playing the video while screen is locked

Expected result:
Mediaplayer-app should be paused and the video output window should show a still image from the video (if not on a black frame)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Victor gonzalez (victor-gonzalez-0)]

I'm experiencing this bug or at least a very similar one, my actual result is that after waking up the phone the video starts to play instead of being paused:

current build number: 420
device name: krillin
channel: ubuntu-touch/rc-proposed/bq-aquaris.en
last update: 2016-09-01 12:30:57
version version: 420
version ubuntu: 20160901
version device: 20160606-ab415b2
version custom: 20160824-991-38-17

video attached

[Victor gonzalez (victor-gonzalez-0)]

Same happening with Frieza:

device name: frieza
channel: ubuntu-touch/rc-proposed/bq-aquaris-pd.en
last update: 2016-09-01 08:59:01
version version: 180
version ubuntu: 20160901
version device: 20160809.0
version custom: 20160824--42-23-vivid