Hello,
Thank you for contacting Rank Math, and sorry for any inconvenience caused.
Rank Math shows the Primary Taxonomy category in the Breadcrumbs: https://rankmath.com/kb/titles-and-meta/#primary-taxonomy
Please go to Rank Math > Titles & Meta > [Your Post Type] > Primary Taxonomy > Select Categories
To show the child category in the breadcrumbs, select the child category as the primary term in the post/product:

Hope that helps.
Thank you.
Thank you so much! That fixed my problem!
It shows parent categories now. Is there any way to show the sub categories under the parent categories?
Hello,
It seems that you have already marked this ticket as already resolved. Could you please confirm?
Meanwhile, please ensure that the child category is selected as the primary as my colleague mentioned above.
Looking forward to helping you.
Thank you.
Indeed I had not carefully read the first response. I thought there was some universal settings to set child categories as primary.
Anyways, it’s now all clear and I have achieved the intended result by changing the configuration on per post basis.
Thank you for helping me! My issue is now completely resolved.
Hello,
Thank you for the update.
We’re glad that this issue is already resolved.
Please feel free to reach out to us again in case you need any other assistance.
We are here to help.
Thank you.