Based on the logs that are provided following are the errors which I can see
Null Pointer Exception. Generally this exception comes when there is any issue with the Work Object opening while extracting the data by BIX Rule.
Error while getting the sequenceNumberAn I/O error occurred while sending to the backend : This error will occur if the DB Query time out happens while retrieving the data for extraction.
Error while doing a commit to pr_log Table ,Error while getting the count from manifest table : Due to the above errors these might be occuring.
This message Could not process" status in the Execution History will appear when there is any issue in records extraction any data issues and it will provide the percentage of successfully executed records and the failed Ins Keys can be found in the PegaBIX.log file.