Are you using the Form 3?
If so, this looks like the ‘layer shifting’ issue discussed at length in this thread:-
http://forum.formlabs.com/t/bad-prints-out-of-brand-new-form-3/25346/177
I would recommend reading through it when you have the time, FormLabs are aware of this issue and are working on a solution. Also I have noticed that there are new PreForm and firmware updates, so I would also make sure you are up to date with those.
Cheers.