1. $ xset r rate 10 50
2. Press and hold any printable key.
3. Now, move the cursor back and forth using the left and right cursor keys. You can see the left key is clearly slower than the right key. Using the down-arrow key or the End key produces the same issue.
ANOTHER (EASIER) METHOD TO REPRODUCE THE ISSUE:
1. $ xset r rate 10 50
2. Press and hold any printable key.
3. Now, move the cursor back and forth using the left and right cursor keys. You can see the left key is clearly slower than the right key. Using the down-arrow key or the End key produces the same issue.