ECC Data Loading process in BW doesn't appear in ECC SM37 for 15 mins

ECC Data Loading process (Example (many different ones experiencing this): Data Source 0DOC_TYPE_TEXT full via Access to SAP Data through Service API) is started in BW from a process chain. A request no. is generated and the process shows active in BW. In ECC, nothing is shown for that Request No. in SM37 until 15 minutes later, and the load completes in 1 second.

It seems to BW that process takes 15 minutes, where in ECC we see the process only takes 1 second, but job does not appear in ECC until 15 minutes after launch in BW.

How to begin to analyze this scenario?

Any pointers are very much appreciated.

Thanks!