'Term_title not working for taxonomy on second level of hierarchie: title not replaced in TITLE tag of Wordpress

I added my own CPT together with a taxonomy.

cpt is called: angebote
taxonomy: themen (hierarchical)
I created my own template file and redirected all calls for the taxonomy to this template file.
installed YOAST SEO

Everything works fine for the first level. But reaching second level of the taxonomy hierachie, the term_title is not replaced in the Tag.

In the YOAST preview (in the backend) the title is replaced.

When loading the page in the frontend the %%term_title%% stays empty, but only for the second level. An example:

Any ideas what I am doing wrong or what I am missing? Thanks a lot for your help :-)

wordpress taxonomy yoast

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