Oil only on one side of engine... help?

I primed my fresh engine for the first time today, and I have the intake on.
Because I have the intake on, I took off the valve covers. While I was priming the engine oil only came out of the passenger side.
I do have all the spark plugs out except 2 on the drivers side because the headers make it a pain to get those plugs out.
Is it possible because I left those 2 spark plugs in the drivers side that it is taking the path of less resistance because of the compression, the oil is only flowing toward the passenger side?

This just seems like it could be bad.

I haven't tried to start it yet.

Any help appreciated.

Thanks much!