Strange article redirect

Hello together,

if i click at my website on the following article:
https://www.mydomain.com/faq/190-topic123.html

my wordpress redirect to the site:
https://www.mydomain.com/topic123/ (This site is also available)

But why wp do this and how i can disable this redirect? (htaccess maybe?)

My permalink settings:
/%category%/%postname%.html
categorie-base: .
I dont want to change these settings because of compatibility reasons from my old website.

I also use WP-Multisite.

Hope someone can help me.

Thank you.
Thomas