FIltering results via category

Hello,

On page of result (within component process->accountability) I have two filter types. Scope works properly showing me results within it, but category returns Error: undefined method `parent' for #<Array:0x00007faeaeaa89d0>

path to this view is: /processes/{:process_name}/f/{:id}/results?filter[category_id][]={:id}

path that do work is: /processes/{:process_name}/f/{:id}/results?filter[category_id]={:id}

so it can be an invalid link.

Best regards

Pauli.

[EDIT:] it's a Decidim 0.21.0 version