Color rule not working when using drill down in scatter chart

Sorry to repost this same Q from last Monday, but I din't really get any replies, so I'm asking again:

When using Power BI desktop, I have a scatter plot that uses a diverging color rule to make points different colors depending whether the relevant metric is positive or negative, which works just as expected. However, when I select a point to drill down to the next level in a hierarchy, the points revert to the default color that appeared before I applied an initial color rule. If I look at the color rule in the visualizations pane, it's still there -- it just doesn't seem to be working.

Any suggestions on what might be causing this (or what I'm doing to cause this) are greatly appreciated. Thanks.