The beam scan (which has been living in the bridge subbasement for a bit now) is in a state of imperfection.
I noticed that:
I took some pictures to try and illuminate the situation - The inverted images are included to make it easier to see the flecks (?) in the slits
I am not sure how to figure out if any bit of the scan is/has been fried.
Pending further investigation, enjoy large error bars in your scan measurements!
PICTURES OF BOTH SLITS ON THE BEAMSCAN HEAD: