Race condition creating Route53 reverse records

For the longest time, this setup worked fine in 0.11.X but with 0.12.20 I’m getting 400 from AWS due to what might be a missing public IP address from the just-created EC2.

This is all I get:

Error: [ERR]: Error building changeset: InvalidChangeBatch: [Invalid Resource Record: FATAL problem: ARRDATAIllegalIPv4Address (Value is not a valid IPv4 address) encountered with '']
	status code: 400, request id: 0f576097-a700-4f65-91d1-29f8f190073a

  on .terraform/modules/single/r53.tf line 10, in resource "aws_route53_record" "r53-record-ext":
  10: resource "aws_route53_record" "r53-record-ext" {

Since this worked fine previously, I’m unsure where to turn for the solution. Use a sleep? Use an explicit dependency?