The issue of "atomicCompSwap" has been found in the driver. The second and third parameters are disordered. It may be fixed released in some days.
I have wrote these code to test glClearBufferData. It seems the buffer is cleared with 0. with no GL_INVALID_VALUE error.
glGenBuffers(8, bo);
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, bo[0]);
glBindBuffer(GL_SHADER_STORAGE_BUFFER, bo[0]);
glBufferData(GL_SHADER_STORAGE_BUFFER, 32 * 16, &data[0], GL_DYNAMIC_COPY);
glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, 32 * 16, &data[0]);
CHECKGL("");
glClearBufferSubData(GL_SHADER_STORAGE_BUFFER, GL_RGB32UI, 0, 0x100, GL_RGB_INTEGER, GL_UNSIGNED_INT, 0);
CHECKGL("");
glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, 32 * 16, &data[0]);
CHECKGL("");
If you still have some problem please attach your application piece also.