H1B tranfers with shorter validity

I received my H1B transfer approval notice with a shorter validity period than the initial approval. Is the new validity related to the duration of my new project or how and who determines it?

How can we know?

You filed the application and you know all the details of your project timing, LCA and client letter duration.

I know, but is it generally with regards to the duration set on the I-129? Since I have heard from people saying that they get a duration cut essentially when they file for transfers. I do not know if this is a normal outcome.
Also in some cases i have heard there are instances where USCIS may shorten the validity irrespective of what date the petitioner has requested.

Thanks for your response.