New to me BRZ w/ IRP Shifter Issues
 

I just picked up a 2013 BRZ (my second). This one has an IRP V3 shifter w/ the reverse lockout. It works great, most of the time, but:

Occasionally, it won't go from reverse into first or second. It can be a little catchy going from first to second, but it definitely goes (I feel like this might have been an issue with mine before, but it's been 5 years since I had mine).

Aside from this issue, the shifter is great. If I'm sitting in my garage, it goes into first/second from reverse just fine, but it's happened a couple times in the real world. I think I understand how the limit screws work on it, but since it goes into gear fine sitting in the garage, I don't see what I'd adjust.

If you remove the center console amnd the shifter trim (Whatever is left of it) you can adjust the reverse lockout pretty easily. See if you can fine tune its position to work better with the IRP shifter.
Using my friend's a long time ago, I recall it being very difficult to do successfully in succession, felt like I had to get lucky.

There are two screws you adjust for lining up 1-2 and 5-6 shift.

Also check the pin that centers the reverse lockout rod. There is a sleeve bushing that takes up slack, without it the rod bends/moves causing misalignment of lockout. I bought one that was missing that sleeve bushing and had same issue with 1-2 not lining up. Found some on Amazon, or contact ARP and they can send you parts.