As Hunter explained and adding to it- it was just a "temporary solution" for lots of complains regarding bugs in the Mini World changes.
The official announcement on October 15 2013 https://www.tibia.com/news/?subtopic=newsarchive&id=2570&fbegind=30&fbeginm=7&fbeginy=2013&fendd=29&fendm=11&fendy=2013&flist=11111111
"Sometimes, even the maddest of mages needs a break to fight off the sanity that slowly creeps back into his mind. From today's server save on and until further notice, the mad mage is on vacation and does some soul-searching at the beach near his tower."
Check the update thread when the Mini world changes were added July 06 2011- https://www.tibia.com/forum/?action=thread&threadid=3434041 - they were filled with many bugs. They been reworked a lot.
Then Masters Voice World Change was revamped on Sept 13 2013 (Major Update 10.02)1 and on October 09 20132- this increased number of bugs in this particular Miniworld (loot issue)see at the thread there and Mirade stating https://www.tibia.com/forum/?action=thread&postid=35529957#post35529957:
"Due to the adjustments that were made with the second part of the summer update, and also last week, the world change has become quite complex scripting-wise. Adding the rules to adjust the world change according to the feedback have made it quite complicated, and also error-prone. It is difficult and extremely time-consuming to maintain and test the world change due to all the possible side-effects, dependencies and conditions that might interfere.
After a careful review, we decided that the best approach is to script the whole quest anew to include the adjustments properly and right from the start instead of spending time with making quick fixes that only complicate the script even more. A proper re-scripting is a project that requires some time (both from content team as well as the test team), though, and cannot be squeezed in between the current winter update tasks and projects. Therefore, we decided to close the world change for some weeks until we find time to do this properly. We will do our best to re-open it as quickly as possible but it may take a while."
1. https://www.tibia.com/news/?subtopic=newsarchive&id=2532
2.https://www.tibia.com/news/?subtopic=newsarchive&id=2565&fbegind=30&fbeginm=7&fbeginy=2013&fendd=29&fendm=11&fendy=2013&flist=11111111
If you wish, you can also find the following document- https://tibia.fandom.com/wiki/Scientific_Contest_(Book)