I think it'll be the case going forward, the last 2 days. there has been a HUGE influx of hashrate. zencash alone is up to 120MH, up from 80MH 2-3 days ago.
expect returns to continue to drop as more asics come online.
MPH switching performed poorly yesterday too. I think we may be seeing the effect of all our asics.
yesterday
2018-07-12 (UTC) 0.00354236 (btc)
vs 3 previous days
2018-07-11 (UTC) 0.00439799 (btc)
2018-07-10 (UTC) 0.00454665
2018-07-09 (UTC) 0.00440286
I had similar results on MPH as well, with yesterday being a down day. What did you get on 7/8/2018? That day was even worse than yesterday for me so I suspect down days are normal.
another poor mining day yesterday at mph - only -> 2018-07-13 (UTC) 0.00344388 (btc)