What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

kind bug

/kind task
/kind feature

What does this PR do / why do we need it:
fix tune failed for DynamicRnn

Which issue(s) this PR fixes:

Fixes #I435J3:DynamicRNN tune failed

Special notes for your reviewers: