summaryLength or summary in config file ignored

[seraphyn]

If I understand Hugo correctly, the specification of summary or summary length in hugo.toml/config.toml is there to make a deliberate hard cut in the blog posts without the More tags.

It happens to me that I get a read more after two empty lines in the text, even though there is no more-tag.

I have tried to disable this behavior with the help of summaryLength. This seems to be ignored.
summary

Both texts also have different numbers of words and characters before the break and

Did I perhaps miss something in Hugo's documentation, or can I change something in the theme so that the behavior no longer occurs.
My point is that these posts appear without a ReadMore

I have oriented myself to
https://gohugo.io/getting-started/configuration/#summarylength
hasCJKLanguage does not apply, I am European

thanks in advance

Christian