Did OnePlus 3 and 3T get an unfinished release of Nougat? (Updated)
Now, a user on the OnePlus forums may have found something which at least partly explains the build's poor performance. While compiling log files for a bug report, user SiMoStro noticed a message which reads: “...this is a DEBUG kernel and it is unsafe for produciton [sic] use. If you see this message and you are not debugging the kernel, report this immediately to your vendor!” In layman terms, this means the code OnePlus shipped with OxygenOS 4.0.1 could potentially be an unfinished version featuring older, buggy code.
While shipping the debug version of the kernel instead of the release one could be simply a developer mistake, the timeline for this update suggests otherwise. After promising 3 and 3T users they'll get Nougat by the end of the year back in November, the smartphone maker pushed out a buggy version on December 31st, the last day of the year. This could mean that the company ran into problems during development, but chose to act on their promise rather than take the time and fix them. So the subsequent problems with this release could be just a result of a hasty promise by a company known for exaggerating in their marketing. In any case, another update, OxygenOS 4.0.2, is rumored to be rolling out in the coming weeks, so hopefully the remaining bugs can be squashed in a timely manner.
source: OnePlus forums via Reddit