Could it be due to a race condition, where both scenarios are accessing the Data Store at the same time, and the one reading from it ran first?
You should also check the Data Store (not just scenario history) immediately Scenario A writes to it, to see if the data is added, because you said “there is nothing there” when Scenario B reads from it.
Also, if you think this is a bug with the Data Store, you might want to contact support.
For complex technical issues or bugs like this, directly contacting support can often lead to a faster resolution. They have access to your specific account details, scenario and scenario logs, server-side logs, and internal tools and resources, which allows them to investigate more thoroughly than what you have access to. Additionally, sharing sensitive information about your situation might not be suitable for an open forum discussion.
You can open a new ticket, or if you are unable to login for some reason, you also can reach support using the contact form on the website. If you manage to get your issue resolved with support, we’d still love to hear about it! Sharing your solution on the forum can help others facing similar problems.
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If you need further assistance, please provide the following:
1. Screenshots
Please share screenshots of the scenario overview, and scenario logs in question? It would really help other community members to see what you’re looking at.
You can upload images here using the Upload icon in the text editor:

2. Scenario blueprint
Please export the scenario blueprint file to allow others to view the mappings and settings. At the bottom of the scenario editor, you can click on the three dots to find the Export Blueprint menu item.

(Note: Exporting your scenario will not include private information or keys to your connections)
Uploading it here will look like this:
blueprint.json (12.3 KB)
3. And most importantly, Output bundles
Please provide the output bundles of the relevant modules in both scenarios by running the scenarios, then click the white speech bubble on the top-right of each module and select “Download output bundles”.

A.
Save the bundle contents in your text editor as a bundle.txt
file, and upload it here into this discussion thread.
Uploading it here will look like this:
bundle.txt (12.3 KB)
B.
If you are unable to upload files on this forum, alternatively you can paste the formatted output bundle in this manner:
-
Either add three backticks ```
before and after the code, like this:
```
input/output bundle content goes here
```
-
Or use the format code button in the editor:

Providing the output bundles will allow others to replicate what is going on in the scenario even if they do not use the external service.
Following these steps will allow others to assist you here. Thanks!