Often this happens because the state is unable to find the wages under the employer they reported on their claim. Most times, we find that the employee is using the wrong Employer Name or Employer Account Number when they filed their claim. If you can provide the correct information prior to filing, this helps eliminate this potential issue.
If you had a recent change in your business due to an acquisition or merger, this could be a source of the issue. The state may need the information on the predecessor (prior) employer if they have not yet completed the transfer of experience in their internal systems.