Conditional Formatting Question

I have a spreadsheet that has multiple columns and nearly 113,000 rows. I'm trying to apply Conditional Formatting to a single column, based on a formula. I know there has to be a simple solution but I have not been able to get this to work correctly.

This data came from someone else. I've done everything I can think of to make sure the cells are clean, no hidden formatting and that numbers are formatted as numbers, etc.

I want to highlight K2 if the value in K2 matches the value in q2, and I want to apply that formatting to all 113,000 rows:

k3=q3
k4=q4
k5=q5
k6=q6


My instinct says the formula should be: =k2=q2. That partially works. It doesn't highlight every instance that it should . . . like it randomly skips some that SHOULD be highlighted.

I've also tried using EXACT, and several variations of IF statements.

I've attached a small sample of my spreadsheet in hopes that someone has an idea.

Highlight K2:K113000 > Conditional Formatting > New Rule > Use a formula
=K2=Q2
Format: Fill color of your choice > OK > OK

It is important to remember that your formula needs to reference the first row that you highlighted in step 1.

This works as expected in your sample.
If this is not working for you, consider attaching a sample where it does not work.