WordPress automatically converts double minus characters -- into single em Dash — characters.
Which is sometimes problematic when you really need double minus. How we can fix this problem? To stoping automatically changing double dashes into the single dash try the below methods.
Possible solution is keep those lines inside HTML <pre> tag. If you use Gutenberg editor then use Preformatted block. So that WordPress keeps that as it is. If still problem does not solve then check if you have installed WP YouTube Lyte plugins then after deactivating that plugins clear all cache then check it will work. It is safe before uninstalling the plugins, take WordPress file and folder and MySQL database backup first. So that if it causes any kind of problem you can restore the previous version.
After that if you have any Caching plugins then clear cash for that page and if you have Cloudflare like tools then also clear cache from there also.
If you find any other better solution please let us know in the comment below. Thanks.