Did I break the filter?

[Trueman]

I was making a batch of fina last night with a kit. When i came to purge the filter the oil ran through as normal for the first 1/2 ml, then loads of air seemed to get into the oil, i.e. loads of tiny white frothy bubbles appeared in the oil as it left the needle, after about another 1/2 ml it stopped and flowed as normal. There is no residure or anything in the fina now, it perferctley clear, of any visible particles or crud. What do you reckon, did I break the filter? Or is this normal?