VK11 Sales price condition lost

Hi guys,

Recently, we encountered a strange question, we have maintained sales price with the aid of VK11, the validity period from 2015/01/01 to 2016/06/30, and we checked SO which was created on 2015/06/08, SO sales price was captured successfully from VK11, however, today, we found VK11 sales price record is lost, and nothing found in price change report, did you guys have the similar situation ever before, if yes, could you share your thoughts & solution with us.

Thanks.

SO created on 2015/06/08