Show excerpt not work

Hi, I’m using the Terms and categories plugin on my homepage (blog page with latest posts) to see all my blog posts in the ALT (hamburger) menu.
However, on each individual post I use the Category Posts Widget plugin to display the posts from the same post’s category in the ALT hamburger menu.
The only problem is that in this second case the 20-word excerpt doesn’t work and the full text of each entry appears. How can I solve that?

Thank you

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