The maxDelay parameter defaults to Infinity:

In the case where the computed delay is larger than the maximum 32-bit signed integer (2 ** 31 - 1), a TimeoutOverflowWarning is emitted by setTimeout, the value 1 is assumed, and we end up waiting only 1 millisecond before retrying, which causes frequent retries.

I have worked around this issue by passing:

socket: {
  reconnect: {
    maxDelay: 2 ** 31 - 1
  }
}