The Scimitar Dreadnought death animations don't play properly. The singularity FX plays as normal, but the ship itself just sits there looking stupid until the effects end.
See here:
http://www.youtube.com/watch?v=aEvVp4W6fcI&feature=youtu.be
All three of the Scimitar models have this problem, based on testing in the Tribble Foundry. And I also saw it happen on Holodeck, at the end of the "Preemptive Strike" mission.