Somebody posted about this back in March but there were no replies.
He was using Windows; I’m using Mac OS and can confirm the same bug.
This doesn’t happen when I’m using HAMRS to log in real time, but if I log with pen-and-paper in the field and then transcribe to HAMRS, I will often tab through fields: first filling in the callsign which automatically populates the other station’s grid square. Then I tab over to add the signal reports, and then I continue tabbing through the Their Park and Comments field to get to the time field to enter the time of the QSO. The moment I tab into the Comments field, the pre-populated grid square information disappears.
Two workarounds: (1) Instead of tabbing, use a mouse or the trackpad to move the cursor to the Time field to set the QSO time. (2) Go back to the callsign field, delete one character and re-enter it thus forcing the software to do a new lookup of the callsign and re-populate the missing grid square field.
Both workarounds are tiresome.
What’s worse is not remembering the bug, and then entering 680 QSO records and having to go back and manually edit 400 of them.