This issue looks to be a known bug to be patched in next release.
Here are the details from HP Knowledge Base:
Test description changes lost when moving from details tab to steps tab in test plan
Change request lifecycle:'
Submitted => Investigation => Action (current state) => Completed (next state)
Defect ID: QCCR1J24516
This is a regression - started from SP3, didn't happen in patch 7 and below.
The scenario is:
- copy a test
- modify description on copied test or any other field in the Details tab of the test.
- move from details tab to steps tab
- modify a step
- go back to details tab of the test, all modifications there are lost.
The patch is the final fix for this issue.
In the queue for consideration in a future release, patch or hotfix