When test generating impressions using Split SDK, on Split user interface Live tail page, no impressions show up, even though treatments are calculated successfully from the SDK side.
All Split SDKs support a de-dupe feature to conserve the amount of impressions posted to Split cloud, the impressions that contain the same user id, feature flag name, and treatment value will not be posted if it they are generated within few minutes.
This is controlled by SDK config parameter impressionsMode. By default the value is set to OPTIMIZED, which will have the SDK use the behavior above.
To post all impressions generated regardless of their values, set the parameter to DEBUG.