Step 1: Create test mission to upload to steam
Step 2: Name the mission and place "&" ampersand in mission description.
I put in the description - "This is a test to see if the "&" ampersand symbol"
Step 3: Publish and Subscribe to your own mission so it appears in your game.
Step 4: Open up Scenarios and find mission
Step 4: Look at mission description and bam.
Hope that makes sense.