Fuel in oil please help part 2

[Jmayberry2011]

So I have a 2013 cascadia with an isx. I
[/size]just did a complete rebuild. I got approx 10,000miles out of it then started noticing my oil level rising. Figured out it was fuel after a couple of days. My mechanic put die in and said three injectors were leaking so I had him change all six. I get my truck back yesterday drove 600 miles and checked oil I got about 2 gallons for fuel in there. Any ideas will be appreciated