pr-labeler: a title with two backport prefixes is labelled from the leftover prefix, with no uncategorized signal #4124

.github/workflows/pr-labeler.yaml:164 strips one [Backport release-x.y] prefix from the PR title. A title carrying two of them keeps the second, and everything downstream then reads that leftover prefix as the PR's scope.

Walking [Backport release-1.2] [Backport release-1.3] fix(linstor): plunger demotes idle-Primary DRBD resources through the script: line 164 strips the first prefix and line 167 adds area/release; the Conventional Commits match at line 171 fails, because what remains still starts with [; the bracket fallback at line 173 then captures Backport release-1.3 as the scope. So linstor never reaches scopeToArea and area/storage is not applied, and kind/bug is not applied either, since no type was ever parsed.

What makes this silent rather than merely wrong is line 218. hasArea is already true from the area/release added at line 167, so the area/uncategorized fallback does not fire and nothing in the run reports an unmapped scope. A single-backport PR with an unrecognised scope at least lands in area/uncategorized and shows up in a triage sweep; a double-backport one looks correctly labelled and gets skipped.

Titles taking this path exist in the history: #2582, #2581, #2576, #2575 and #2526, all of them [Backport release-1.2] [Backport release-1.3] over a conventional subject.

Either fix closes it. Loop the strip so every leading [Backport ...] is removed before parsing, or anchor the bracket fallback so it refuses a scope starting with Backport . The loop is closer to intent, since one title can legitimately carry more than one backport marker, and it also restores the kind/* label that the current path drops.