patternMergeVariantArrays: false - not working

[perriard]

I have "patternMergeVariantArrays": false in my config, and yet it still merges my array.

I am using Pattern Lab Node v6.14.6 on Mac, with Node v12.18.3, with Twig template engine.

data.json has 4 items in the breadcrumb
sub-page.json has 2 items in the breadcrumb
article-page.json does not have a breadcrumb array

Expected Behavior

sub-page.html has 2 items in the breadcrumb
article-page.html has 4 items in the breadcrumb

Actual Behavior

sub-page.html has 4 items in the breadcrumb - the first 2 from sub-page.json and the last 2 from data.json
article-page.html has 4 items in the breadcrumb

Steps to Reproduce

as above