This bug results from not initialising variables appropriately before using them.
The junk value is written to the glusterfs.quota.limit-set xattr in the backend for the directory on which it is desired to set the hard limit. The same junk value, therefore, gets displayed in the output of 'quota list'.
Initialised the local variable to all zeroes before using it.
Now the correct value of the soft-limit is displayed in the output of 'quota list'.