Eventually what happens is enough people leave because of the bad run that it drops below 300gh, then things gets better. Thing is, they get too good, then people come back and it goes back up above 300gh.
I can't conceive of a scenario where a scaling problem could be responsible for bad luck. Scaling problems causing more stale shares or more orphaned blocks? Sure. Scaling problems making math stop working? How, exactly could the size of the network have an impact on the likelihood that random numbers are below a defined target?
Just because I can't conceive of it, doesn't necessarily mean it isn't possible, but given an understanding of how this all works, it seems extremely unlikely to be related to scaling.
I'm stating from what I've observed. Every time the pool hash rate goes > 300gh, things go south. When it drops back down, things go better. It could be coincidence that it happens every single time I guess.
When we're below 300gh, yes, we have bad runs, but the good runs always outnumber the bad. When we get above, the trend reverses.
M