For early clinical material, if reprocessing occurs during a batch, but this reprocessing step is not yet validated, can the batch be released if it is found, during an investigation, that there is not product impact?

Yes, the batch should be releasable if in agreement with your filing. Validation of the process for clinical trial APIs is not expected. So, if we don’t expect it for the original process, we would not expect it for reprocessing either.