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
           },