Tooltips on note timestamps not showing for issues

In an issue, hovering over timestamps in notes doesn't show the popover.

In the console I see:

raven.js:364 Uncaught TypeError: Cannot read property '_route' of undefined
    at xn.get (vue-router.esm.js:556)
    at e.value (index.js:5653)
    at e.value (index.js:5205)
    at e.value (index.js:5170)
    at e.value (index.js:5796)
    at e.value (index.js:5605)
    at e.a [as handleEvent] (raven.js:360)