I'm thinking primarily of Matt Prior and Stuart Broad here but I'm sure there are other examples. Both are players who exemplify the swashbuckling lower middle order dasher when clad in white, but who seem to forget how to put willow to leather in the limited overs formats.
Why is this? Prior's test SR of 66+ stands comparison to some of the cream of ODI dashers. He scores his test runs more rapidly than Pietersen, Symonds, Flintoff, de Villiers, Haddin & Ponting to name but half a dozen. Put him in pyjamas though and it's a sorry tale of woe. His MO does perhaps rely on a few productive shots (very strong on the cut and off his pads), but opposing captains never manage to stymie his scoring in tests by blocking those areas so there must be more to it than that.