Problem summary
When you run an A/B test email in HubSpot, the metrics for the two variants do not add up in Funnel the way you expect. One variant shows the combined total of both variants, while the other shows little or no data. The numbers in Funnel match what HubSpot's API returns.
Error message or symptoms
One email variant reports far more sent, opened or clicked events than it received on its own, often close to the combined total of both variants. The other variant reports very few events or none.
When does this occur
You send an A/B test (split test) email in HubSpot
You compare per variant email metrics in Funnel against the per variant numbers in the HubSpot UI
You sum the two variants in Funnel and expect them to match the campaign total
Root cause
This is expected HubSpot API behavior, not a Funnel issue. HubSpot's API reports A/B test email metrics aggregated under the primary email variant, so email A carries the combined metrics for both A and B. This applies to both the legacy API version and the latest version, so upgrading the API version does not change the result.
Solution
This is expected behavior and there is no Funnel-side fix, because HubSpot aggregates the data before it reaches Funnel. To read the metrics correctly:
Treat the metrics on the primary variant (email A) as the combined total for the whole A/B test.
Do not add the two variants together. Email A already includes email B's events, so summing them double counts.
When you only need the campaign total, use the primary variant figure as is.
Workaround
If you need standalone numbers for each variant, create a custom metric in Funnel that subtracts email B from email A. Compare against the HubSpot UI to confirm the split before you rely on the result.