We recently uncovered a couple of bugs in the Zooniverse code which meant that the wrong question text may have been shown to some volunteers on Zooniverse projects while they were classifying. They were caught and a fix was released the same day on 29th November 2018.
The bugs only affected some projects with multiple live workflows from 6th-12th and 20th-29th November.
One of the bugs was difficult to recreate and relied on a complex timing of events, therefore we think it was rare and probably did not affect a significant fraction of classifications, so it hopefully will not have caused major issues with the general consensus on the data. However, it is not possible for us to say exactly which classifications were affected in the timeframe the bug was active.
We have apologised to the relevant science teams for the issues this may cause with their data analysis, but we would also like to extend our apologies to all volunteers who have taken part in these projects during the time the bugs were in effect. It is of the utmost importance to us that no effort is wasted on our projects and when something like this happens it is taken very seriously by the Zooniverse team. Since we discovered these bugs we worked tirelessly to fix them, and we have taken actions to make sure nothing like this will happen in the future.
We hope that you accept our most sincere apologies and continue the amazing work you do on the Zooniverse. If you have any questions please don’t hesitate to contact us at firstname.lastname@example.org.
The Zooniverse Team