Joining an agency before it finalizes my security clearance

Forgive this long post, but details seem relevant:
The agency where I was fortunate to receive and accept an official offer is pressing to set a start date. A start date will trigger a “release date” requested from my current agency, and my obligation to give notice. The new agency has only preliminarily cleared me for what might be a “high risk” clearance-level position. I say “might be” because the posting said clearance level was “other,” but a security person there described it as “high risk.” Should I give up my current, decent GS-scale job to start the higher-paid, CG-scale job, and risk losing the new job if denied “high risk” clearance? Has anyone ever left one job for another, been terminated for being denied clearance at the new job, and then gotten their old job back?

More details: OPM/DoD has started its investigation. DoD-contracted special investigators have interviewed me, my current supervisor, a current co-worker, and my next-door neighbor. I have lived many places and held many jobs, so there’s a lot for investigators to verify. I was told they will interview my husband, who has not been contacted.

Last year I was found “unsuitable” for a position with the Department of Justice. No reason was given, but the conditional offer was rescinded. Will my current investigators see that DOJ decision and whatever materials it was based on? And would it bear on the current agency’s clearance decision?

Under the new system of all federal clearances handled by OPM/DOJ, how much information transfers from one investigation to another? I would be grateful for advice/insight/considerations as to whether I should give up my current job before the new agency finalizes my security clearance. Thanks, all.

DOJ shares information with OPM and DCSA. The impact from the suitability denial will depend on the denial reason.

Thank you very much for responding. I hope the new agency deems less consequential whatever DOJ had deemed unsuitable. In your experience, how often do people preliminary cleared to start a job then get terminated for lack of the necessary final clearance?

I thought most all clearances and public trust investigations were being hired by DCSA now?

Sorry, I mistyped. Meant to say “Under the new system of all federal clearances handled by OPM/DoD,” (not DOJ). The HR contact specifically said that after preliminarily clearing me to start, it handed off the investigation to OPM. I suspect that’s an outdated description, since the investigator who interviewed me introduced herself as a DCSA contractor.