Description of problem:
Almost everytime twitter videos on the twitter feed fails to play. Spamming the replay button does not help.

Version-Release number of selected component (if applicable):
66.0-9.fc29

How reproducible:
Randomly (Not always)

Steps to Reproduce:
1. Try to play a video on twitter
2.
3.

Actual results:
Video doesn't play

Expected results:
video should play as in other browsers

Additional info:
I got this JSON info from an addon:
"MediaInfo":{
"HTMLMediaElement":{
"autoplay":false
"buffered":[]
"controls":false
"crossOrigin":NULL
"currentSrc":"blob:https://twitter.com/d785d16b-71ad-4d7e-a905-d0fcde4fcfe0"
"currentTime":0
"defaultMuted":false
"defaultPlaybackRate":1
"duration":57.072993
"ended":false
"error":NULL
"loop":false
"mozAudioCaptured":false
"mozFragmentEnd":57.072993
"muted":false
"networkState":2
"networkState_name":"NETWORK_LOADING"
"paused":true
"playbackRate":1
"played":[]
"preload":"none"
"readyState":1
"seekable":[
0:{
"start":0
"end":57.072993
}
]
"seeking":false
"src":"blob:https://twitter.com/d785d16b-71ad-4d7e-a905-d0fcde4fcfe0"
"srcObject":NULL
"volume":1
}
"HTMLVideoElement":{
"height":0
"mozDecodedFrames":0
"mozFrameDelay":0
"mozHasAudio":true
"mozPaintedFrames":0
"mozParsedFrames":0
"mozPresentedFrames":0
"videoHeight":360
"videoWidth":640
"width":0
}
"videoPlaybackQuality":{
"ratio":"--"
"droppedVideoFrames":0
"corruptedVideoFrames":0
}
"mozMediaSourceObject":[
0:{
"sourceBuffers":[
0:{
"start":0.073333
"end":3.091927
}
]
}
1:{
"sourceBuffers":[]
}
]
"debugInfo":{
"Container Type":"MediaSource"
"Audio Decoder(audio/mp4a-latm, 2 channels @ 44.1kHz)":"ffmpeg audio decoder"
"Audio Frames Decoded":"1"
"Audio State":"ni=0 no=0 wp=0 demuxr=0 demuxq=0 decoder=0 tt=-1.0 tths=-1 in=1 out=1 qs=0 pending=0 wfd=0 eos=0 ds=0 wfk=0 sid=100"
"Video Decoder(video/avc, 640x360 @ 0.00)":"shutdown"
"Hardware Video Decoding":"disabled"
"Video Frames Decoded":"0 (skipped=0)"
"Video State":"ni=0 no=0 wp=1 demuxr=0 demuxq=0 decoder=0 tt=-1.0 tths=-1 in=0 out=0 qs=0 pending:0 wfd=1 eos=0 ds=0 wfk=0 sid=4294967295"
"Dumping Data for Demuxer":"7f2b11a48400"
"Dumping Audio Track Buffer(audio/mp4)":"mLastAudioTime=0.096553"
"Audio Track Buffer Details":"NumSamples=130 Size=67160 Evictable=0 NextGetSampleIndex=1 NextInsertionIndex=130"
"Audio Track Buffered":"ranges=[(0.073333, 3.091927)]"
"Dumping Video Track Buffer(video/mp4)":"mLastVideoTime=0.000000"
"Video Track Buffer Details":"NumSamples=0 Size=0 Evictable=0 NextGetSampleIndex=4294967295 NextInsertionIndex=-1"
"Video Track Buffered":"ranges=[]"
"Compositor dropped frame(including when element's invisible)":"0"
"MediaDecoder=7f2b10da3600":"channels=2 rate=44100 hasAudio=1 hasVideo=1 mPlayState=LOADING"
"MDSM":"duration=57073000 GetMediaTime=0 GetClock=-1 mMediaSink=7f2b1f5b1940 state=DECODING_FIRSTFRAME mPlayState=1 mSentFirstFrameLoadedEvent=0 IsPlaying=0 mAudioStatus=idle mVideoStatus=waiting mDecodedAudioEndTime=96552 mDecodedVideoEndTime=0 mAudioCompleted=0 mVideoCompleted=0 "
"VideoSink":"IsStarted=0 IsPlaying=0 VideoQueue(finished=0 size=0) mVideoFrameEndTime=0 mHasVideo=0 mVideoSinkEndRequest.Exists()=0 mEndPromiseHolder.IsEmpty()=1"
}
}

Tried with also webrender and GL composting on.