First build after Marketplace installation fails — Data Connection source returns empty URL

After installing a Marketplace product, the first build of a transform that uses an external data connection fails with:

MissingSchema: Invalid URL ‘’: No scheme supplied. Perhaps you meant https://?

The transform fetches data from a REST API using rest_api_source.get_https_connection().url, but on the first build the URL resolves to an empty string. The subsequent retry (triggered minutes later) succeeds.

Logs:

[GLEIF][spark-transform] LEI 20260524: fetching from 
[GLEIF][spark-transform] Downloading 
ERROR: LEI 20260524 UNEXPECTED ERROR [MissingSchema]: Invalid URL '': No scheme supplied.

Expected behavior: The data connection source should be available on first build after installation.

Actual behavior: First build gets an empty URL from the source. Retry succeeds, suggesting a timing/initialization issue with the data connection during installation.

Question:
Is there a known delay between product installation and data connection source availability? Is there a recommended way to ensure the external source is fully initialized before the first build triggers?