Hugo switched to using Goldmark as its markdown processor. As part of its security model, directly included HTML tags are blocked and that is why your content is not generated.
To fix it in your config file place the following:
[markup]
[markup.goldmark.renderer]
unsafe = true
My example is using TOML notation.
** Please do note that your direct HTML inputed tags will not be sanitized, but I guess you know what you are doing and what placing in the content.