Issue with uploading solution for Exercise 86

Data Structures and Algorithms Specialization
Exercise 86 evaluation seems to work incorrectly even when the solution is correct.

My code:

// Setup
var myDog = {
"name": "Happy Coder",
"legs": 4,
"tails": 1,
"friends": ["freeCodeCamp Campers"],
"bark": "woof"

// Only change code below this line
delete myDog.tails;

Your browser information:

User Agent is: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0.

Challenge: Delete Properties from a JavaScript Object

Link to the challenge: