We don't know it's a total bail. It may just be a partial sell-down lightening. Say you'd taken up your 17c entitlement which has gone up moving your weighting up to 7%. You may take some profits to bring yourself down.
Allied to the point above. They may have sniffed the wind, being a long short - absolute return fund. Cu has run hard, they can see the long forward buy's had peaked short term versus the sells so they traded. It's happening across the board in Cu developers.
They've been a long-term holder and probably couldn't tolerate the non-performance any longer given it is reflected in the results of their funds.
In fact overall the SP has gone up so they're being better than replaced. At least Ellerston had the stones to support the co- this far. All IMVHO.