Kirk,
Sometimes a programmer can take a feature request too literally. I wonder if that has happened here. Running a full ingest process as a separate deferred repeat process that is fully reliable could be daunting or even nearly impossible. Yes, that is technically what the original request appeared to suggest as a possible method. But customer-centered listening might require parsing the expressed need as something entirely separate from the expressed possible methodology. Easier said than done, especially when mired in a giant version development process. But perhaps a worthwhile starting point when looking at feature suggestions more generally.
Looks to me like the need expressed is to have PM ingest to the primary drive in a way that operates at full SSD speed without being slowed by the limitations of the speed of a slower secondary destination drive. Looks like you just came up with a way to do this. Solution: don't do a deferred identical ingest process. Instead, have PM ingest first to the primary destination (SSD drive in this case) and then copy everything over to the secondary drive. Much less complex than what the initial request appeared to suggest as a method. Problem nearly solved.
Since there may be a less complex way to meet the requested need for SSD speed, the next step could be to explore possibly ways to automate that without being bound to only what was seen as an implied method in the initial request. I'm not a programmer, but it seems natural to consider the feasibility of making a preference or a button available to instruct PM execute the ingest to the primary location followed by copy from primary to secondary location. The customer would not have the full flexibility available by designing and running separate ingest processes. But if the flexibility matters less to the customer than speed, perhaps the customer might find such a new automated feature valuable as an alternative to needing to remember to carry out a second process every time.
I write all this without any personal stake in the prioritization of the requested feature. Just suggesting a potentially useful way to look at things. Not seeking a specific response. Best wishes for timely completion of version 6.