What could cause the differences in I-526 adjudication timeline?

Each DS-260 application is unique from another application depending on the biographic information of individual investors. As a result, the processing of each application is affected by whether an applicant has met the requirements, for example, providing all necessary and required information and documents. It is a common fact, that applicants provide their information at different times and pace, thus one should expect that this fact always affects the processing of each application even when it involves investors in the same project. The same reasoning applies when you are comparing projects, the rate of approvals in one project will most certainly be different from another project as the nature of investors, the compliance issues relating to individual investors may affect how one project progresses or not.

Every case is its own thing. USCIS has said they try to group investors, so perhaps early investors wait longer until a few more pile up, so the later ones get adjudicated faster relative to the earlier ones. USCIS adjudicated less than 500 I-526s last quarter and has 17,000 pending.

It appears that this is random. USCIS does not use a first in first out system of adjudication. They allegedly batch process but even this does not explain the system because it can only be described as generally haphazard adjudication with most cases presently taking about 2 years to process.

Different adjudicators, different sources of funds and other issues. There are countless variables.