Apply hover postprocessor on updates (#5039)

holoviews/plotting/bokeh/element.py

@@ -1334,15 +1334,15 @@ def _postprocess_hover(self, renderer, source):
         if not isinstance(hover.tooltips, util.basestring) and 'hv_created' in hover.tags:
             for k, values in source.data.items():
                 key = '@{%s}' % k
-                if key in hover.formatters:
-                    continue
                 if ((isinstance(value, np.ndarray) and value.dtype.kind == 'M') or
                     (len(values) and isinstance(values[0], util.datetime_types))):
                     hover.tooltips = [(l, f+'{%F %T}' if f == key else f) for l, f in hover.tooltips]
                     hover.formatters[key] = "datetime"
+
         if hover.renderers == 'auto':
             hover.renderers = []
-        hover.renderers.append(renderer)
+        if renderer not in hover.renderers:
+            hover.renderers.append(renderer)
 
     def _init_glyphs(self, plot, element, ranges, source):
         style_element = element.last if self.batched else element
@@ -1541,6 +1541,9 @@ def update_frame(self, key, ranges=None, plot=None, element=None):
 
         if 'hover' in self.handles:
             self._update_hover(element)
+            if 'cds' in self.handles:
+                cds = self.handles['cds']
+                self._postprocess_hover(renderer, cds)
 
         self._update_glyphs(element, ranges, self.style[self.cyclic_index])
         self._execute_hooks(element)