Jquery ui tabs strange hash problem

I am using jQuery UI tabs (but this also happened with a much simpler bit of code too).

When I come into the page, the # value brings the selected tab to the front eg

/posts/#tab-4

opens tab 4 as you would expect.

However with all except the default tab the viewport scrolls to the bottom of the page rather than, as one would expect, to the anchor position.

any ideas.

the live code is here;

https://development.sacredtrust.org/workshops/pollen
clicking through from
https://development.sacredtrust.org/workshops/
a good instance is
https://development.sacredtrust.org/workshops/pollen/#84

and in Safari, my hashs are stripped out altogether

any ideas?