OK I get it now!
16.10.19 08.41.16 <--> 16.10.19 08.42.07 jdlog://1953130900751/
Note that this log was generated with the Settings --> Plugins --> filesmonster.com check box NOT selected for "Add only premium-only links whenever a premium account is availalbe and add only free-only-links whenever no premium account is available?".

Here is the log with that check box selected:
16.10.19 08.44.13 <--> 16.10.19 08.44.35 jdlog://3953130900751/

In both cases, the premium only link is generated (i.e. no multi-part download), and I don't have a premium account setup in the Account Manager.