Remove contrast enhancement near edges in heatmap

[e123]

At the moment, there is contrast enhancement around each colour region in the heatmap. I indicated it with circles in the screenshot attached. These vertical edges look like real orders and might be misleading. I would like to have an option to turn this feature off.

Note, this is not a bug and is not related to the screen settings. The Bookmap support team confirmed that this is an intentional contrast enhancement feature.