Reporting this on behalf of the DSpaceDirect service team. We ran into an issue where a restore of content ("restorefromaip" task) from DuraCloud using the Replication Task Suite fails if DuraCloud does not return a "content-length" header. While this header is useful, it does not seem to be required, and the entire process fails if a single header is missing.
This behavior was reproduced with Replication Task Suite v3.4 and DSpace 5.x, but may affect all versions of RTS.
Specifically, this line of code was throwing a "java.lang.NumberFormatException: null" error: https://github.com/DSpace/dspace-replicate/blob/dspace-replicate-3_x/src/main/java/org/dspace/ctask/replicate/store/DuraCloudObjectStore.java#L79
The fix/workaround is to not assume that the "content-length" header is always provided. Instead, when it is missing, the Replication Task Suite can determine the downloaded content size by simply checking the size of the downloaded file. A PR to fix this bug will be posted shortly.