Public Trust Expiration

I tried searching this, but couldn’t find an answer. I was hired for a federal contract position (USMS) around the same time last year (June/22). The employer only gives the final offer and start date after everything (Medical/Background) has been finalized. So, I was granted a Public Trust (filled out the SF85); however, the process took 7-8 months which I thought was kind of long for a Public Trust. I ended up not taking the position as I was given employment by another agency prior to this offer.

So, does the Public Trust expire in the case that I did not take the position? I was under the impression that the determination would still be good as it was finalized/granted and hasn’t even been a year. I know for the position, that once granted and in/hired; there is no periodic reinvestigation as would be the case if holding a S or TS clearance. That position has come open again in my area and I expressed interest in reapplying for the position, but was told by the hiring manager that I would have to go through the entire process again. I understand the medical portion, but I thought I would still be good to go with the security determination. Thanks!