FAST Merit List Issue – Campus Preference Changed After 2nd Merit Li

In the 2nd merit list, I was offered Software Engineering at FAST Multan. However, when the portal updated this morning, it suddenly changed to BBA at Islamabad.
My first campus preference was Islamabad, but I wanted to continue with the SE offer that I had already received for Multan.
I visited the admissions office today, and they asked me to write an application. They said the issue would be resolved.
Has anyone else experienced something similar? Is it possible that my SE Multan offer will be restored? Also, how long does it usually take for FAST to resolve these kinds of portal issues?
Any help or similar experiences would be appreciated.