When Brave Shields are enabled on YouTube, every video starts with an
artificial black screen delay (2-10 seconds) accompanied by an
“Experiencing interruptions?” popup. The video does NOT actually have
a connection issue — it has already been downloaded into RAM but
YouTube’s JavaScript intentionally holds it from playing to punish
ad blocker users and push them toward YouTube Premium.
This is confirmed by Wireshark analysis shared by other users in this
community — the buffer is full, the delay is purely artificial.
No custom filter fixes this since it is enforced by YouTube’s
server-side JavaScript, not the browser.
Besides using a profile like 289wk mentioned, using FreeTube is a good alternative for when YouTube injects Javascript of this nature.
@fanboynz usually finds fixes for this, but realise that these interruptions is a “cat-and-mouse” game between YouTube and adblocker developers.
That’s why using FreeTube helps; it loads the videos only, without the Javascript/ads/nonsense. It’s available here if you’re interested: https://freetubeapp.io.