Strictly speaking, there is no line police. All you need to do is set your view to "High Quality" and not "Draft Quality".
A defect in the display and management of edges is sometimes encountered when a cut has been made on an assembly that has intersecting components (usually in the case of assemblies with screws).
In the document options, it is possible to specify a font, but usually you have to leave the setting to "Default".
The one from jmsavoyat was more precise: you have to put the threads in high quality to see them as usual; otherwise, in rough quality, we have a hidden line edge at the bottom of the thread and threads that remain above the components.
Thanks to you 2 in any case for your quick answers