Soap Api cannot query multiple data sources

Hey. We have this issue as in the title. We thought the issue is in soap itself. We had diffrences in output between consoles debugger and soap api with the same relevance query. We tested it and it appears that soap query only one data source -> the first one. And it should the whole webreports. We have 5 data sources in one web reports. Do You know what can be the issue and how to troubleshoot it? Many thanks!