Can you let us know if you are using two TD's for one DMA?
In that case the data the will first be transferred to that buffer whose TD has been given in the API: CyDmaChSetInitialTd(uint8 chHandle, uint8 startTd). This function Sets the initial TD to be executed for the channel when the CyDmaChEnable() function is called.
For more details, please refer to the appnote 'PSoC 3 and PSoC 5 Getting started with DMA': https://www.cypress.com/documentation/application-notes/an52705-psoc-3-and-psoc-5lp-getting-started-dma
The appnote comes with an example project that shows how to use multiple TDs with a single channel and chain them to one another. In this example the ADC data is sent to two separate RAM buffers, one after the other, using a single DMA channel and two TDs.
Please feel free to correct me if my undertanding of the situation is not correct.