Hi,
It is essentially a debug message and is there for our ( developers ) benefit. It points to an issue in the Populator that Matt was trying to track down. It was left in basically because it was useful to know how often etc. this was a problem and also whether it makes any difference to final renders. Most of the time it doesn't and the message can be ignored.
It is a warning message rather than an error. We do have two levels of messages. Errors with the red icon are for things which have gone wrong. The warnings with the yellow icon means something might not be quite right or is a message to let you know you might want to change something, but it's probably not a big deal.
Of course it obviously has caused people some consternation and as TG2 has reached a wider audience we can't reassure everyone it isn't really a problem. It is still handy for us to know it's happening and if there are any problems with populations as a result, and of course with any luck Matt will be able to track down the root issue at some point. That it hasn't been possible so far shows what a hard thing it has been to pin down.
Regards,
Jo
