olex2c needs libreadline.so.8 (RHEL8 has .so.7, vendor lib/ only .so.6), so the Ra build node could not complete the post-install ld.so --list and the guard aborted. Add Fedora 40 readline-8.2 to the sysroot rpms (needs only the host libtinfo.so.6) and make step 7 print the listing, warn on host libs missing on the build node, and die only on a genuine patchelf/sysroot failure.