The bug report claims the memory usage keeps increasing and never decreases. This is not reproducible, on many devices and browsers. The memory usage can increase with any game actions (as it should), but it also decreases gradually (as it should).
If anyone can actively reproduce this, please provide us with your reproduction steps and system information and it will be reviewed again. Until such a time as the issue can be confirmed, there is nothing further we can do.
ETA: Tagging the innogames account on your posts won't give you any results, just fyi.