In the "childrencategorylist_sm" field, the IDs of Sitecore Experience Commerce categories may be duplicated:
"childrencategorylist_sm":["b893c063-6238-ed57-700d-72862c56038d|b893c063-6238-ed57-700d-72862c56038d|c1114488-2d5f-39c7-5e16-42f64d5f2d4a|c1114488-2d5f-39c7-5e16-42f64d5f2d4a|871c3b62-ce96-ad61-dabe-10db020f02c5|871c3b62-ce96-ad61-dabe-10db020f02c5"]
This causes duplicated categories on front-end site.
To resolve the issue, upgrade Sitecore XC instance to Sitecore XC 9.0.2 or later.