Segmentation fault QScroller::grabGesture

After commit "QScroller: maintain activeScrollers as a QList, not a QSet" 8b8e53f7267 https://codereview.qt-project.org/#/c/214637 (qtbase.git), qt_activeScrollers was changed from QSet to QList and bug was introduced. Same scroller can be registered multiple times and only one is removed in the end. This sometimes (depends of luck) crashes our embedded application after scrolling
QTextBrowser or closing and opening window with gesture capture.

I tested also with qt 5.9.7 and old version of code works perfectly.

Used API calls:
QScroller::grabGesture
QScroller::ungrabGesture