This ignores the 48 and does 12. This is especially an issue when navigating back and forth between the archive and an item as it does not return to the same place you clicked from.
The more per page only works when you click it from the dropdown on page
Do you have any caching plugin enabled? Or even a cdn, server level cache? If so, could you try clearing it? My attempts to access the link actually ended up in an error…