Cluster visible on while actually off

[Ecconia]

Sometimes a whole cluster stays on, while it obviously should be off.

Not sure what exactly causes this, but its probably some multi-threading issue. While I thought it is thread-safe.

When the cluster gets updated the next time, it fixes itself.

Difficult to reproduce.

[Ecconia]

There has been a major rewrite in the wire-meshing code.
Since then the bug has not been seen again - does not mean its gone.