The banner URL is valid, but googleusercontent intermittently drops the banner
request when the channel page fires the banner + avatar + ~16 thumbnails at once;
the browser then negative-caches the miss, so the banner stays broken with no
auto-retry (even though the same URL loads fine on a fresh request). On error we
now retry a few times with a ?r= cache-buster (a fresh URL that bypasses the
negative cache), and only fall back to the blank bar if it keeps failing (a
genuinely dead URL). Fixes the broken-banner on channel pages like BASSHUNTER.
peter
26230b52e8