Inserting into collection: "Error: key $super must not start with '$'"

Please forgive my ignorance if this is an easy fix but I have seemed to look everywhere and haven’t found a solution.

I am running the code below and it’s returning this:

Exception in setTimeout callback: Error: key $super must not start with ‘$’

The problem is specifically the Round.insert().

Meteor.setTimeout(() => {
    let percentage = parseFloat(Decimal.random(10) * 100).toFixed(2);
    let secret = Randomstring.generate(12);
        players: [],
        pot_value: 0.00,
        percentage: percentage,
        secret: secret,
        hash: SHA256(percentage + '-' + secret),
        active: true,
        status: 'pending',
        skins: [],
        created_at: new Date(),
        end_time: 0,
        snipeAttempts: 0
}, 3000);

It was a problem with the hash. Problem solved.