why does Pages reject my font changes and revert to original font?

In every writing program I've ever used, changing fonts, font size, color, etc is super straight forward. You get the cursor where you want your text to go, you select the new size or font you want, and then you start typing and that's it. If you're typing in order with your cursor at the very end of the document on Pages, it works this way too. BUT...

If you realize mid-paragraph that you want to change a font, Pages is a disaster. You set your change, and then for some reason Pages "selects" the cursor turning it blue. Then if you then start typing, Pages discards the font changes you've made and starts typing with the old font. No other writing program behaves like this. Why is this happening? Is there a setting I can change? Or is just a glaring design flaw?

Here's an example of this thing in action: Pages weird font behavior - YouTube

Many thanks to anyone who can help me solve this. I'm trying to do outlines in Pages (so lots of bold headings to add in) and it's driving me insane.