Not a bug at all. The analogRead inputs a precise 10-bit value, 0-1023 for the precise voltages 0/1023 (0 v) through 1023/1023 (5v, 3.3v or whatever your reference voltage is). Your XOD patch displays that 0.0 to 1.0 (normalized) fraction with 2 significant digit precision, rounded to the closest value. The Arduino IDE, however, gives you the exact integer 0-1023. Ok. Now for your particular value or similar.
The value 188 corresponds to the fraction 188/1023 which is 0.1838.
That value, 0.1838, rounded to the nearest 2 significant digits is 0.18.
The next closest value would be 0.19, which is further away from the actual, many digit decimal value, reported by Google as 0.18377321603. It actually repeats as all fractions do. (after 30 digits)