In order to help you in the best possible way, I’ve taken this issue to my wider team and upon discussion, they’ve informed me that there is an ongoing technical issue of sampling in GA UI which was confirmed yesterday by our Engineering team and a few of other clients are also affected due to this issue. Hence, we’re seeing sampling in the custom reports by including any date range beyond Oct 14th, 2018.
In order to confirm this, I’ve again taken a look into your GA Account and could confirm that sampling is only visible by including the date range beyond Oct 14th. Having said that, we’re seeing sampled data in API due to the same issue even after using Resource Quota.
As a general information, I’d like to share that there are multiple tables for data processing in GA and one of the data generation pipelines was stuck due to some technical issue and it resulted in blocking the precompute data generation pipeline since Oct 15, 2018. It is this precompute pipeline which processes ad hoc queries. Due to this, API results are also being affected (As API queries also fetch the data in ad -hoc manner).
That said, we’ve already escalated this to our Engineering team for a thorough investigation, and they’re actively working on it on a high priority. As a workaround, we suggest you pulling up the unsampled reports for the analysis in the meantime. Apologies for the inconvenience this may have caused you.