SwiftUI charts, how do I align these X axis labels correctly?

Hi there, so I have this chart that's taking in a Date for it's x values and a time interval for their y values. For some reason, the labels aren't centering on each bar, the only fix I see is to add an offset to each label but that seems hacky.

My code:

Chart {
                ForEach(weekBreakdownArr, id: \.startDate) { bd in
                    BarMark(
                        x: .value("Date", bd.startDate),
                        y: .value("Duration", bd.durationWorkDone),
                        width: .fixed(15)
                    )
                    .foregroundStyle(Color.redYarn)
                    .cornerRadius(2)
                }
//...
            }
           // shownXValues are just the start dates in an array
            .chartXAxis {
                AxisMarks(position: .automatic, values: shownXValues) { val in
                    AxisValueLabel {
                        Text("Th")
                            .useAppFont(size: 12, relativeTo: .body, weight: .regular)
                    }
                }
            }