The SRAM and local memories have an ECC protection. After power-on, SRAM and the corresponding ECC bits hold random values. Therefore, depending on the combination of values, an ECC block (usually 64 or 32 bits) might or might not be displayed as a bus error.
When an application is programmed to FLASH, it is the responsibility of the boot code to initialize the SRAM. Only if it is intended to run an application from SRAM (e.g. as early test or for flash programming), the SRAM must be initialized through the debugger using the command:

Data.Set EA:0x40000000--0x4000BFFF %Quad 0x0000000000000000