@dkhutch is correct above that ACCESS-OM2 built with GCC did used to crash at runtime.
However, the latest release of ACCESS-OM2 (2026.02.001) includes fixes to MOM5 and libaccessom2 to allow compiling and running with GCC.
@davemunday, you will need to update your spack.yaml to prevent runtime errors like those reported by @dkhutch. Would it be simplest for one of us to update the https://github.com/ACCESS-NRI/ACCESS-OM2/tree/api-v2-archer2 branch and for you to pull from there?