I have written an app in Python using Dash 2.18.2. In that app I have a map with a cycling track and several graphs to show distance vs. speed, distance vs. power etc. I have written an JS-script to show hover-info on the graphs when hovering over the map and vice versa. I use therefore 'customdata' that is encapsulated in the hoverdata. with this Dash code:

 customdata = np.stack((df0['Dist'], overall_focus, df0['Lons'], df0['Lats']), axis=1)
 hovertemplate=('Dist: %{customdata[0]:.1f}<br>'+
 focus+': '+ '%{customdata[1]:.1f}<br>'+
 '%{customdata[2]:.6f}<br>'+
 '%{customdata[3]:.6f}<br>'+
 '<extra></extra>')
 
 
 # Create the scatter map figure with plotly.express
 fig_trck = px.scatter_map(
 map_style=map_mode,
 center={'lat': center[1], 'lon': center[0]},
 zoom=zoom,
 lat=overall_lats,
 lon=overall_lons
 )
 
 # Update traces with custom data and styling
 fig_trck.update_traces(
 customdata=customdata,
 hovertemplate=hovertemplate,
 marker_size=3,
 marker_color=overall_focus,
 marker_colorscale='Rainbow',
 marker_showscale=False,
 line_width=2,
 line_color='Blue',
 mode=mode
 )

When I use Plotly 5.24.1 it gives this result in the DOM:
Object
points:Array(1)
0:
bbox:{x0: 894.0113118377704, x1: 896.0113118377704, y0: 354.0555201566335, y1: 356.0555201566335}
curveNumber: 0
customdata :( 4) [33519.2, 22.104, 4.507961, 51.843206]
lat:51.843206
lon:4.507961
pointIndex:4327
pointNumber:4327
[[Prototype]]:Object

when I use Plotly 6.0.0, I get this result:
Object
points : Array(1)
0:
bbox: {x0: 894.0113118377704, x1: 896.0113118377704, y0: 354.0555201566335, y1: 356.0555201566335}
curveNumber:0
customdata : undefined
lat:51.843206
lon:4.507961
pointIndex:4327
pointNumber:4327
[[Prototype]]: Object
length: 1

Can anyone explain this? Is it a bug or is customdata removed to another position in the DOM?