Forms side has checked this exception and found that it is thrown by library shared from Directory Server. So we've add new tag 'Directory Server' and 'Directory Server' team would follow this post.

Hi Timothy, I have tried to reproduce this issue, but I have no success with the reproduction.

Could you please provide us the corresponding logs in Event Viewer and the related operations you did when the issue occured? So we can better investigate this issue and find out if we can handle it.

Thanks in advance!