When calling update_layout() on a figure, xaxis_range does not update correctly when margin_b is specified

plotly                    6.0.1

I create a figure like so

fig = go.Figure()
fig.add_trace(go.Scatter(x=np.arange(100), y=np.arange(100)))
fig.update_layout(xaxis_range=[50,None])
# fig.update_layout(margin_b=20)
fig.show()

Expected behavior
fig.update_layout(xaxis_range=[50,None]) (Line 3) should set the min xaxis value to be 50, while keeping the max value intact. It does this correctly (Correct: x-axis is from 50 to 100). Interestingly, when I click the modebar to download the plot as png, the xaxis range is incorrect in the output image.

Bug
If you uncomment the line fig.update_layout(margin_b=20) (Line 4) which adjusts the bottom margin, the x axis range is back to its original value unaffected by Line 3 (Inorrect: x-axis is from 0 to 100). Interestingly, if you double click the plot to reset the axes, the x axis changes to the updated value (50 to 100).

Note:
Weirdly, if I change Line 3 to fig.update_layout(xaxis_range=[50,100]) (specify 100 instead of None) and keep the margin_b line uncommented, the behavior is correct again.

Start by running the minimal Python example using update_layout(), comparing margin_b=20 with an explicit xaxis_range maximum and with None. The report names no source file or test; done means the x-axis remains 50 to 100 in the interactive plot and downloaded PNG when the bottom margin is set.