It is not possible to use the same UART in both bootloader and bootloadable.
Actually bootlader and bootladable should be seen as two separate projects in the same flash. When bootloader transfers the control to the bootloadable all the configurations of the peripherals will be re-written according to the bootloadable project. So you have to place UART in both Bootloader and Bootloadable.
But if you are using BLE component inside PSoC and if you want to use the BLE component to bootload the application ideally you have to put BLE component in both bootloader and bootloadable. This consumes a lot of flash because BLE stack occupies larger area in flash.
For this special case, we have developed Fixed stack and Upgradable stack BLE OTA projects where both bootloader and bootloadable uses the same BLE stack. You can have a look at the following appnote:
Hope this helps.
This explains the problem.