I love running and won't stop, but I can certainly provide my personal anecdote about how it is inhibiting a "bulking phase."
I increased my calorie intake by ~500-700 per day over a point where I was maintaining my weight (now at 3400-3600 cal/day). I have also been following the P+C/P+F concept for the most part, which I was not doing prior to this intended bulk. I continued my same exercise regimens, following the MH Homegrown Muscle program (now in Phase 9 - strength building phase) and running 20-25 miles per week on 3 or 4 days. I expected to gain ~1 LB. per week, but here is my graph of progress over 5 weeks. According to the trendline, I have gained a whopping 1.5 LBS. in five weeks! On the other hand, I do seem to be responding to the dietary changes with improved strength in most exercises.
I haven't been doing intervals with my runs for some time, although I do intend to do more of those as I train for a local 10K in November. OTOH, my local terrain is very hilly, which provides some interval-like effect... at least it sure seems like it.
I can also attest that my bodyfat levels are far lower at this point in my life (almost age 38), when I have been combining weight training and running, versus times during my 20's when I only did running for exercise and was as much as 20 LBS. lighter.