I was going to say that is awful - makes using an enlarger for sensitometer look like a bad idea.
Until I realized. I keep the enlarger locked at the height to make an 11x14 print from 4x5 neg. So I am only using the sweet spot near the middle.
I placed the film squarely under the lens, but positioned the test strip on the left-hand side - so maybe I fortunately avoided the hot-spot at dead center.
And I am using a grid light source, not condenser.
What is your light source (does the lens really have a hot spot in the middle or do condensers play into it)?