In 2014, when the relationship between nascent smartphone maker OnePlus and alternative software maker Cyanogen Inc. was souring, the company began work on a new in-house version of Android, which would eventually become to be called OxygenOS.

The team behind OxygenOS was largely made up of members of the former custom ROM group Paranoid Android, many of whom in early 2015 relocated to Shenzhen to work more closely with the company's hardware and marketing teams.

The goal was to have OxygenOS, which at first was less feature-rich than the version of CyanogenOS that arrived on the company's first phone, ship with the OnePlus 2 in early 2015. In the subsequent months, the development team built up what we now know of as the software that ships on the OnePlus 3, the latest unlocked, direct-to-consumer smartphone from the upstart manufacturer.

Long hours and insufficient resources at the company in the run-up to the launch of the OnePlus 3 lead a number of people on the OxygenOS team to leave.

But in mid-August, OnePlus released a community build of an upcoming version of OxygenOS, dubbed OxygenOS 3.5, which confers some big aesthetic changes to the OnePlus 3's near-stock aesthetic. The changes were not universally lauded, but since the release much of the core community has taken to its new look and updated feature set. In the days following OxygenOS 3.5, OnePlus announced through a series of interviews that it was merging its OxygenOS development team, which has heretofore focused on the North American and European markets, with that of HydrogenOS, a separate version of the software for OnePlus's growing Chinese audience.

While the messaging from OnePlus depicted a company with a singular goal of building efficiency through consolidation, in order to offer faster software updates for all OnePlus owners, Android Central has learned that prior to the merger, many of the core members of the OxygenOS team left the company, including the Head of Mobile Product, Helen Li. Long hours and insufficient resources in the run-up to OnePlus 3's launch led to a number of OxygenOS team members striking a deal to terminate their contracts just after the phone's release, according to people who didn't want to be named because they signed non-disclosure agreements. As a result, OnePlus CEO Pete Lau had no choice but to merge the remaining members of OxygenOS, some of whom are only signed on until the end of 2016, and HydrogenOS.

According to these people, despite a 3:1 ratio of OxygenOS users to its Chinese market counterpart, OnePlus was disproportionately pouring resources into HydrogenOS, causing strain between the two teams and leading the subsequent talent purge.

In a statement to Android Central, OnePlus said, "We have unified our software platform and team to increase efficiency and speed up our software updates. This has been in the works for a while now because maintaining two separate software platforms is not sustainable for such a small, young company with big ambitions." The company confirmed that OxygenOS and HydrogenOS will remain separate products aimed at distinct markets for the time being, and that the "back end" change is "an important step in the right direction."

Read more: OnePlus 3 review

But our sources say that this move was never intentional, and came out of a staff exodus that took the company's management by surprise. Since the unification, the HydrogenOS team has begun the slow process of merging code from the two projects, the first versions of which have been the OxygenOS 3.5 community build and the subsequent 3.5.1 update, released a week later.

The chief designer responsible for championing and maintaining OxygenOS's "Nexus-like" aesthetic is no longer with the company.

Projects that uniquely identify OxygenOS, like the Shelf, are currently being tended to by the remaining OxygenOS members, who are assisting in the transition before they, too, leave. Similarly, the chief designer responsible for championing and maintaining OxygenOS' "Nexus-like" aesthetic, is no longer with the company, so it remains to be seen whether the now-unified product, dubbed OnePlus OS, or OOS, will shift more markedly towards a custom look and feel, similar to Huawei's EMUI software layer, or Xiaomi's MIUI, which looks and operates drastically different to what North American Android users expect.

While this news is undoubtedly a setback for fans of the OnePlus 3's stock-like software experience, it's unclear how the internal changes will affect the quality of the phone's release going forward, or whether, under a single team, the company can stick to its promise of more frequent updates without any negative consequences.