Dotnet authentication clock skew.

If you use dotnet JWT authentication check your TokenValidationParameters, and make sure you have set ClockSkew to reasonable values. By default, it is set to 300 seconds (5 minutes). That make your JWT tokens valid for extra 5 minutes.

/// <summary>
        /// Gets or sets the clock skew to apply when validating a time.
        /// </summary>
        /// <exception cref="ArgumentOutOfRangeException">If 'value' is less than 0.</exception>
        /// The default is <c>300</c> seconds (5 minutes).
        [DefaultValue(300)]
        public TimeSpan ClockSkew
        {
            get
            {
                return _clockSkew;
            }

            set
            {
                if (value < TimeSpan.Zero)
                    throw LogHelper.LogExceptionMessage(new ArgumentOutOfRangeException(nameof(value), LogHelper.FormatInvariant(LogMessages.IDX10100, LogHelper.MarkAsNonPII(value))));

                _clockSkew = value;
            }
        }