Question for the adjudicators on here and anyone else with insight: Will adjudicators ever let a file sit and get delayed on purpose? If so, why?
Like maybe adjudicators are waiting for some more time to pass from a certain incident. Maybe they are waiting for an applicant to return from an overseas trip. Could more investigation still be going on during adjudication as well so the applicant’s file just sits until that is over? Other reasons?
I’m not an adjudicator but I have been an adjudicatee 
many times. My theory is that there is some kind of triage where cases get a first look and the easy ones go through first, or maybe they get routed to the newer adjudicators. Cases with issues get routed to a smaller pool of experienced adjudicators. This helps them meet their timeline goals.
Just my own theory and if I was in charge of adjudications its what I would do. But once it gets to an adjudicator they need to finish it as promptly as possible.
The reason an adjudicator would hold up an adjudication is if more information was needed without formally reaching out the the applicant with an SOR, or it may be in 2nd level review and approval. RSIs are notoriously slow to come back from DCSA.
While we’re waiting for @Marko let me speculate that RSI is something like Request for Subject Interview or some term where the adjudicator needs more info and so they ask an investigator to contact the subject again. In my long and checkered past I have also been contacted directly by an investigator.
Everything has to be reviewed, I’ve even heard of a third level review! I suspect the first level of review is routine but anything beyond that may be issue-based, that is, certain issues were found in the case and require additional scrutiny.
An RSI is reimburable security inquiry focused to flush out specific issues and are sent in to DCSA after an investigation is closed and the adjudicator needs more info in order to make a determination.