Unfortunately, this is the same date I moved off 2 large sections of the site into subdomains - so I am unsure if this somehow has something to do with that...
I don't think it has got anything to do with the subdomain spin off.But AFAIK, you have the perfect data for a pandalized site and what you have described is how it looks in pandalized sited that I had come across. i have one question to you. Are these metrics from Google Analytics?
Some more facts:
I had noticed this increase in direct traffic in one pandalized site, way back in March (around 7-10).These visitors would just come in and bounce off.I had raised a question on it in this forum and some pointed me towards sabotage using mechanical trunk. The reason why people referred me to sabotage via mech. trunk is because the visits were from countries all around the world and not limited to any identifiable region.
However, the direct visits dropped off after two weeks but then DT as as a % of overall traffic increased by 10% while SE traffic % dropped by 10% and it remained that way until July.It didn't stop there.All other metrics like bounce, avg. time on page were terribly screwed and it remains bad to this date - Nothing seem to help in improving them or restoring these metrics to what it was pre-panda.
This month I am seeing another fresh sabotage like increase in Direct traffic. The only guess I can make out of this is some force is acting to screw something (may be user engagement metrics).