GL Batch with PERIOD as NULL

Hi All

We are on R12.1.3. We have a handful of GL Batches created with Period as NULL. The corresponding JE Headers and Lines do have a GL PERIOD, and the batch itself is Posted but for a NULL GL PERIOD. These Batches were created through a WebADI interface. We get the below-listed error while querying the batch from the App

1. Can a GL Batch be created w/o a GL Period
2. What's causing the GL Batch to be created w/o a GL PERIOD.
3. Would it create any process inconsistency, or reporting issues? The Batch is in POSTED status, so I guess no accounting issues.