FL to 12.1.2 I did the following things: Add->Channel->More plugins> Manage plugins. Once the FLStudio Plugin Manager pops up I added plugin search paths, clicked on verify plugins and started scan, once it finished ...
FLStudio 12.2 build 3 64bit
CPU: Core i7 6700HQ
RAM: 16GB DDR4
STORAGE: SSD+HDD
Here is a video of the issue, there is an audible click going up to -18dB on master channel when adding Toneboosters Reelbus ...