'Read More' links changed to 'listen' but not if you access blog from menu

Site URL: https://newcommunity.org.uk/sunday-talks

A few months ago I managed to change the default 'read more' link at the bottom of each of our Sunday talks to 'listen'. Each talk is a blog post. 

However, I have just discovered that when I access the page from the menu (Resources>Sunday Talks) it reverts to saying 'read more' rather than 'listen'. Not a massive deal, but I reckon most people who are accessing the page will come in via the menu. If I refresh it, it then reverts back to 'listen'.

Given that I'm not entirely certain how I fixed it in the first place, any ideas as to how I can make sure it always says 'listen' regardless of how you access it? I'm attaching a picture of what I found in the Custom CSS section that might be how I fixed it in the first place.