Fullcalendar scheduler - header horizontal scroll error

Question

I'm using fullcalendar scheduler v.5.3.2. Horizontal scroll seems not to be working in timeline view header, whith a custom view of 6 weeks (resourceTimeline).

Here is my code:

calendar = new FullCalendar.Calendar(calendarTimeline, {
    
    initialView : 'resourceTimelineSixWeeks',
    views : {
        resourceTimelineSixWeeks : {
            type : 'resourceTimeline',
            duration : {
                weeks : 6
            }
        }
    }
});

And here is the error i'm seeing because the header is not moving at all: displaced_header

I've tested it without a customview, and in IE 11, Chrome and Firefox with same bad result. ¿Is this a bug? ¿Someone who knows how to solve it? Fullcalendar demo works fine: https://fullcalendar.io/docs/resourceAreaColumns-grouping-demo

I also haven't found any info about this problem here or in github.