diff --git a/jdaviz/configs/specviz/plugins/unit_conversion/unit_conversion.py b/jdaviz/configs/specviz/plugins/unit_conversion/unit_conversion.py
index 89fcfac88a..f4427fff6f 100644
--- a/jdaviz/configs/specviz/plugins/unit_conversion/unit_conversion.py
+++ b/jdaviz/configs/specviz/plugins/unit_conversion/unit_conversion.py
@@ -181,6 +181,14 @@ def _on_glue_y_display_unit_changed(self, y_unit_str):
             )
             self.hub.broadcast(GlobalDisplayUnitChanged("sb", self.sb_unit_selected, sender=self))
 
+        else:
+            # if cube was loaded in flux units, we still need to broadcast
+            # a 'sb' message for mouseover info. this should be removed when
+            # unit change messaging is improved and is a temporary fix
+            self.hub.broadcast(GlobalDisplayUnitChanged('sb',
+                                                        self.flux_unit.selected,
+                                                        sender=self))
+
             if not self.flux_unit.selected:
                 y_display_unit = self.spectrum_viewer.state.y_display_unit
                 self.flux_unit.selected = (str(u.Unit(y_display_unit * u.sr)))