[Bug] Attribution Model over-attributes Direct Entry, even without using User ID

[atom-box]

What happened?

A user writes to us:

One of the key reasons we selected Matomo is the default attribution model: last touch non-direct just like UA. ( FAQ )
But when we leveraged the multi-touch attribution tool, the revenue attributed to the direct channel was larger than the last touch non-direct number, which shouldn't be possible

Example, for a given visitor:

• Visit 1: Arrives via Google search.
• Visit 2: Arrives via Direct entry, and then has a conversion.
• The report in Ecommerce >> Sales says the attribution is Direct

In contrast to two similar issues.

• Unlike PG-3034 (private issue) there is no use of the MCCA plugin (Multichannel Conversion Attribution)
• Unlike #21020 there is no use of User ID.

The user adds:

The August 4th comment (in #21020) and much of its thread is touching on the User ID portion and potential generation of new IDs, but we're not using that functionality at all, so I wasn't sure how to respond to that piece. The issues we're seeing our tied around interactions that are already tied to the same visitor.

What should happen?

If the first visit was from a referrer, and the second visit is direct entry, the conversion should accrue to the referrer.

How can this be reproduced?

Visit a website via a search engine referral.
Wait 30 minutes.
Visit by direct entry.
Generate a conversion event.
Check the report in Ecommerce >> Sales >> Channel type

Matomo version

5.1.0

PHP version

No response

Server operating system

No response

What browsers are you seeing the problem on?

No response

Computer operating system

No response

Relevant log output

No response

Validations

• Read our Contributing Guidelines.
• Follow our Security Policy.
• Check that there isn't already an issue that reports the same bug to avoid creating duplicates.
• The provided steps to reproduce is a minimal reproducible of the Bug.

[AdamMcAddEm]

We are experiencing this issue, and it's a bit annoying that we can't leverage this feature that we're paying for.

[Blueside2k]

We are experiencing exactly this problem. We have already tested many approaches and have not found a solution.
We need a clean channel allocation according to the "Last Non-Direct" attribution model for our internal marketing reporting.