Ahoy devs !
Just as in the title I state
Full HD youtube play went back to normal, flawless
→ on Haiku 64 bit Nightly hrev58174 : nightly was just slightly related and in mainly QMPlay2
→ on R1B5 64 bit hrev57937 + 118 : especially for QMPlay2, but Falkon too
If you had not done anything like so … then YT itself was the culprit.
I experienced stumbling YT play in QMPlay2
(audio was continuos meanwhile the picture stopped, then oince just jumped to synced part, played for a while then the erratic way started again. It was not as used to be on R1B4 64 bit and Nightly that I used
meanwhile the transition from R1B4 to R1B5)
Then I checked the YT play in Falkon, set to FHD intentionally, so I saw possible reason behind :
there were frequent loading signal showed for some seconds then continued again the playing and so this way … load, playing, load, playing, load, playing …
It was interesting as the system load was the same as earlier on R1B4 and nightly, and there were no reason to have network bandwidth or any other network accessibility issue.
Then I switched back to Nightly immediately and there it was lesser observed, but was slightly there too.
I had not reported as I hoped in my bad luck turns into golden days of recent Haiku usage.
It happened : D
So wether thanks to you or not … I am grateful and thank you! 
