No that is not at all abnormal. Within limits and those limits may be rather large, nock height will vary some degree from one shooter to the next, and how you yourself are shooting. For example 3 under tends to require a high nock point than split finger. Also it can kind of depend on how you're measuring it.
For example take the line that is exactly 90 degrees to the string and that also intersects the point of the rest or shelf that the arrow sits on. Where that line intersects the string we will call 0" nock height. Now lets say just for the heck of it that your arrow nock is 3/16" thick. If we put the nock set on the string 1/4" above the point that we have already established as being 0" then really your arrow is only 1/16" above absolutely level, if even that because there is also the arrow diameter itself which is surely larger than the nock is thick. Get it? Gawd I hope so!
So how did you measure? Are you really nock point 1/4" high or is your arrow actually nearly level?