When switching all unlocked special modules (all five) on Thar’Ga or Tai’Kin, sometimes hovering or clicking with a mouse on a new special module won’t work at all.
Occurrence: Common
How to replicate this bug:
Make sure that all 5 special modules on Thar’Ga or Tai’Kin are unlocked/researched.
Apply any special module, then try to select another one and click on it. After a few attempts, it will fail to apply.
This issue can only be solved by exiting Ellydium interface and accessing it again.