B19, OS X 10.11
Don't know if I'm misunderstanding Qrecall's capabilities or if this is a bug...

Background: Have both a laptop and a desktop Mac running same software and much of the same data on both so I thought I could use a single archive and take advantage of QRecall's de-duplication to drastically reduce the amount of data I backup and the need to have separate backups, one for each computer.
My QRecall archive "Backups.quanta" resides on an external USB drive which I move between computers.
Each computer has an internal drive partitioned into two uniquely named volumes.
Laptop has volumes "A" & "B", iMac has "C" & "D". Both running same QRecall beta level.

Plug external drive into iMac, create a new archive and capture "C" & "D". Captures complete with no errors. Viewing archive shows disk icons for "C" & "D" as expected.
Quit Qrecall, unmount external drive and now move & plug it into the laptop.
Open QRecall, open existing archive. Viewing archive shows disk icons for "C" & "D" as expected.

Now, attempt to capture volume "A" or "B" -- the capture starts, captures the 200+GB (identifying about 90% as duplicate). A new layer is created but the newly captured volumes (A and/or B) *do not* appear in the "Backups.quanta" window! It is not possible to browse them or access the data on them even though QRecall captured them.
The Log file shows "Capture to Backups.quanta", no error messages, but no message it finished.

Huh?
Where are they and their data?

Volumes "A" & "B" are probably in a different owner.

A single QRecall archive can capture data from multiple owners/systems/identities. These owners are at the top-level of the archive. After your first capture, the browser defaulted to the iMac owner, which has captured volumes "C" & "D".

After capturing volumes "A" & "B", your archive's browser view is still looking at the volumes captured for the iMac. Use the navigation bar at the bottom of the window and navigate to the root (archive) level of the browser tree. There you will see two owners, "iMac" and "Laptop" (or, specifically, the owner names you gave them when you entered your identity keys).

Drill into "Laptop" and you'll see the two new volumes.

If the owner names are too similar, you can rename them in QRecall > Preferences > Identity Key (for that system). The new names will appear in your archive (immediately for you local identity, or after the next capture for the other).