Ended up being a case of I should have known better. I always figured the filter on the petcock would be good enough and an inline filter was overkill.
I pulled the float bowl off and found some little slivers of black plastic which ended up being bits of the threads from the cap to my reserve bottle. Pulled the petcock and found a nice little tear in the screen. Needless to say the screen is cut off the petcock and I have a nice paper inline filter now.