Sometimes it works perfectly, other times not, it seems.

Is the problem it will not load (Tap to fix?)
We have had this in the past with previous versions of AB v3, (whereas v2 worked reliably each time). We have noticed this with iReal Pro and various other apps either as Input or other apps loading in Effect, so it seemed to affect a number of apps, not just iReal Pro. Each app would either load easily, or would get the ‘Tap to fix’ error.
Often we got them to load by following the error instructions, force quitting the app, force quitting AB, opening apps first then AB (or vice versa), reboot device, and various other similar combinations to get them all loading.

(We also noticed that some apps had not been updated for a year or two so presumably were coded originally for previous versions of AB, sometimes loading, other times, not.)

With recent minor updates, either related to iOS, or AB or both, we noticed an improvement in loading, especially iReal Pro, although sometimes it is not perfect. And there are still problems loading other apps into AB also.

The results are the same with AUM (Reload errors). I’ve noticed iReal Pro will load, or if not, the error message shows, and usually the instructions for loading it work. I get this happening with other apps loading in AUM also.

Obviously it’s frustrating if you want to load a number of different apps into AB as some will load than others, but vary randomly each time you try it. I’m not sure the order of loading each app (input and effects) makes any difference either.

Since AB v2 worked in a better way, hopefully they will find a way to make this more reliable.
AudioBus provide connection code for audio developers to use within their apps and as this is updated, we update it in iReal Pro so it complies with their app.

Have you tried the error message procedures that come up when there is an error? (Sometimes they do not work until you play around with it for a while.)
And do other apps sometimes error when loading into Input or Effect too?