Thunderbird inserting unnecessary line breaks in plaintext mode since TB78

Hi,

I have exactly the problem described in https://support.mozilla.org/en-US/questions/1307490 (thread is archived so I can not reply there). This is how the problem looks like. Ususally a composed mail text is displayed like this after sending the mail:

Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

But since I think TB 78 it sometimes looks like this disturbing the plaintext format a lot:

Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore
magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit
in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit
anim id est laborum.

I’ve never touched the thunderbird config for mailnews.wraplength (my value there was and is 72).

Is there any other way to avoid the line breaks?