Losing files from Siemens Prisma AutoSend sessions

Description of issue
Autosend on Prisma works as follows: Upon completion of individual series, the Prisma sends DICOM to XNAT. If a series is long then the series previously sent may hit the sessionBuilder timeout and begin archiving/merging.

Issue seems to occur under the following conditions:
1. Project is set to autoarchive merge setting.
2. Session has already been partially archived. (In other words, some of the series have already been sent and timeout for sessionBuilder has occurred, causing those series to be autoarchived. However, series acquisition is still ongoing.)
3. A new series (call it series 14) is received, sessionBuilder timeout occurs and sessionBuilder is started up (Starting job: sessionXmlRebuilderJob) to merge this series into existing session.
4. One or two seconds after Starting job: sessionXmlRebuilderJob appears in the logs for series 14, a new series (call it series 15) is sent from the scanner.
5. Result is that series 14 gets archived properly. One of several things happens with archiving series 15:
a. All the files for series 15 make it to SCANS/15/DICOM, however, the scan is not catalogued, so it appears to be missing.
b. Only some of the file for series 15 make it to SCANS/15/DICOM, and also the scan is not catalogued, so it appears to be missing entirely.

Better info, logs etc. in linked ticket.