Fix a UB in morpheel

src/d/actor/d_a_e_oct_bg.cpp

@@ -502,6 +502,11 @@ void daE_OctBg_c::core_fish_attack() {
         } else if (field_0xbaf == 0) {
             cXyz cStack_68(current.pos);
             f32 in_f31;
+
+            #if AVOID_UB
+            in_f31 = cM_rndFX(80.0f) + 100.0f;
+            #endif
+
             cStack_68.y += 200.0f;
             if (fopAcM_gc_c::gndCheck(&cStack_68)) {
                 f32 groundY = fopAcM_gc_c::getGroundY();