No tooltip, no hover panel, still `hover_line_color` is ok in multiline plot

I am trying a HoverTool on a multiline plot. I am not getting the hover displayed, so I went back to this really simple block of code

    ("(x,y)", "($x, $y)")

# Initialize our plot figure
p = figure(title="A map of the area",width = 1200, height = 1200\
         # , tools=TOOLS+[hover]\
           , toolbar_location='above',tooltips=TOOLTIPS)


p.multi_line('x', 'y', source=source, color='grey', line_width=0.5,hover_line_color='red', hover_line_alpha=1.0)

The line that I go over with my mouse gets colored in red, so the mouse-plot interaction is working, but I do not see any “panel” showing x,y. I have also tried other things such as several columns, but I never get a panel with the tool tip.

the javascript has strange errors (as usual), see below. Any idea what rookie mistake I might be doing here?

ncaught TypeError: Cannot read property '6' of undefined
    at b._update (bokeh-2.2.2.min.js:569)
    at b.<anonymous> (bokeh-2.2.2.min.js:240)
    at o.emit (bokeh-2.2.2.min.js:181)
    at p.inspect (bokeh-2.2.2.min.js:258)
    at b._inspect (bokeh-2.2.2.min.js:569)
    at b._move (bokeh-2.2.2.min.js:569)
    at b.<anonymous> (bokeh-2.2.2.min.js:497)
    at b.<anonymous> (bokeh-2.2.2.min.js:240)
    at o.emit (bokeh-2.2.2.min.js:181)
    at d.trigger (bokeh-2.2.2.min.js:497)
_update @ bokeh-2.2.2.min.js:569
(anonymous) @ bokeh-2.2.2.min.js:240
emit @ bokeh-2.2.2.min.js:181
inspect @ bokeh-2.2.2.min.js:258
_inspect @ bokeh-2.2.2.min.js:569
_move @ bokeh-2.2.2.min.js:569
(anonymous) @ bokeh-2.2.2.min.js:497
(anonymous) @ bokeh-2.2.2.min.js:240
emit @ bokeh-2.2.2.min.js:181
trigger @ bokeh-2.2.2.min.js:497
(anonymous) @ bokeh-2.2.2.min.js:497
_trigger @ bokeh-2.2.2.min.js:497
_mouse_move @ bokeh-2.2.2.min.js:497
(anonymous) @ bokeh-2.2.2.min.js:497


See this bokeh discourse topic, which mentions a bug in hover tooltips for multi-lines with Bokeh 2.2.x.

Thanks for pointing me at this bug discussion. I am using 2.2.2 which seems to be affected.