A320 reverse thrust issue - user error?

I've been flying the default A320N on short hops around California in FS2024 and have been getting more comfortable with it. One issue I've been having is after landing and vacating the runway, when I try to taxi to my gate and apply thrust, the engines go into MREV mode and the thrust reversers open. They work as normal if I use my mouse to apply thrust in the virtual cockpit.

I've had no issues with taxiing to the runway for departure, this only happens after landing. I'm assuming I'm missing something on the checklist as I mostly just skim through it but is there anything that immediately comes to mind as to why this is happening?