Cannot enter a custom waypoint in the MCDU

I’m having difficulty entering a custom waypoint. I have my ‘From/To’ set up, I go to the data screen, page 2, hit ‘stored waypoints’, then ‘new waypoint’ but when I try to input anything it doesn’t work. It could be anything random at all, but nothing enters into any of the fields. Even the lat/long. :(. This happens on the A320NX (mod) but on the vanilla A320 I can’t even access page 2 of the data index, the next page button doesn’t work (but it works on other pages like INIT)

I have tried with 0 addons and am using the Steam version.

How can I fix this?

When I use Simbrief, the flight is synced into the tablet perfectly fine, displaying the custom waypoints (coords) and I can add the plan to the MCDU using Simbrief but for some reason the MCDU ignores the custom waypoints.

Also, when I load the pln (saved from Simbrief) in the main menu before launching the flight, it works perfectly fine…So why can’t I do it manually?