Slider jumps forward in steps of two - need to move one back for odd step numbers

[n01r]

I observed that the slider, when using the plus and minus buttons, moves forward in steps of two and to reach odd numbers one has to use the minus button from the next larger number. The figure number updates but the slider label does not.

openpmd-viewer version: 1.6.0
ipywidgets version: 8.0.4

[ax3l]

In more detail:

• for -, the slider widget does not refresh, but the plot does.
• for +, the image jumps two steps forward.