Weird system config, weird system behavior

I learned about Signal Tap II and did some minimal internal logic tracing. The 8-bit byte writes place, for example, "0x0505" on the data bus when writing 0x05 to the external RAM part. Since we don't have byte lane enables happening, that explains the funkiness when updating our RAM location. When updating memory via the nios2-console, it writes a 16-bit value even when doing byte writes.

What is not clear is how nios2-console "knows" what the other half of the byte is. I assume it must read the location, modify the corresponding upper or lower byte, and then write the 16-bit result or maintain a local cache or something. I didn't too any in-depth tracing using Signal Tap, but am guessing something along these lines is happening.