I run a similar setup on my Sr20det
vavle cover vented to catch can with -10an drain/block vent.
Works great and highly recommend but as you found be sure to continue to run the valve cover vents to catchcan as well as the block to catch can.

 

@RSMike how is oil getting into the IC? I hope seals are all fine. I see mine leaks/sprays a tiny bit of oil on the valve cover. maybe i could use another breather port
Time to try an oil drain-back and/or double breather vent

 

I'm guessing the turbo didn't like the pressure in the block, so it's come out of the seals (compressor side). Only thing I can think of.

I'm guessing turbo seals. I'll go back to using all 3 vents as it worked perfectly. I like to tinker and play around, which 50% of the time results in something bad happening - haha

 

That's my guess also I did that to my stock turbo... it was bleeding oil straight to my downpipe

 

@RSMike I know this is a bit of a thread revival, but nearly 2 years on, are you still using this breather location, and if so, any negative side effects.
The aim is to run a similar setup this year and hopefully with one of your sumps

 

It's been working well.
I had another local customer do this breather mod on the block only, and it reduced the oil in the catch can around 75%.
I want to try breathing from the block to the head directly, below the baffles. Then use the normal breather ports on the rocker cover. Rather than having a line from the block going around to the catch can also.