Updating remaining estimate with REST causes original estimate to also be modified, regardless of the state of time spent field

Summary

The following command can be used to reproduce this problem:

 curl -D- -u user:password -X PUT --data "{\"fields\":{\"timetracking\":{\"remainingEstimate\":\"3d 1h\"}}}" -H "Content-Type: application/json" http://url/rest/api/latest/issue/issuekey

Result:

      "timetracking":{  
         "originalEstimate":"3d 1h",
         "remainingEstimate":"3d 1h",
        ....
      },

Setting originalEstimate updates remainingEstimate also, so attempted workaround by resetting originalEstimate to whatever it was before the change does not work.

Steps to reproduce:

1. create an issue
2. set the original estimate (eg: 2h)
3. log work in the issue (eg: 10 mins) . Refer to screenshot BeforeRESTCommand.png
4. run REST command to update the Remaining Estimate
5. refresh issue view screen and the Original Estimate is also updated . Refer to screenshot AfterRESTCommand.png

Workaround

Two possible workarounds:

1. The issue does not occur if you enable time tracking 'Legacy Mode'
2. Always set both, originalEstimate and remainingEstimate. This way it works fine:
   • REQUEST:

     {
     "fields": {
     	"timetracking": { 
     		"remainingEstimate": "55m",
     		"originalEstimate":"2h"
     		}
     	}
     } 
     

   • RESULT:

           "timetracking":{  
              "originalEstimate":"2h",
              "remainingEstimate":"55m",
              "originalEstimateSeconds":7200,
              "remainingEstimateSeconds":3300
           },