@wellandwhole , Yes, I got a false negative from Galleri. My PC in particular seemed to play hide and seek.

Summary:

Whipple w/ all clean margins and lymph nodes on 6/15/2022
Clean MRI and perfect CA19-9 on 7/15/2022
Negative Signatera on 7/27/2022
Negative Galleri on 10/3/2022
Negative Signatera on 10/26/2022
Tumor spotted on MRI at Whipple site (1.3 cm) and lymph node on 10/26/2022
EUS Biopsy negative on 11/1/2022
Positive Guardant 360 on 11/14/2022
Positive Signatera on 12/1/2022
Tumors confirmed growing (2.1 cm) by MRI and rapidly increasing CA19-9 on 12/17/2022

So... it managed to hide from 3 DNA-based tests (two Signateras and one Galleri) before being detected on MRI, and even managed to hide from the EUS biopsy despite the rapid growth from zero in mid-July to 1.3 cm at the end of October. Rising CA19-9 on tests in that span was my biggest hint of recurrence. I was surprised and disappointed the DNA tests didn't pick up on the tumor within 3 weeks of the MRI detection (and especially the biopsy that same week!). Those let to about 7 weeks of delay in my starting treatment for the recurrence.

Anyway, I'm really interested to hear how your Galleri report turns out and exactly when it was done in your overall time line. Of course, I'm hoping you get a good, true negative out of yours!!!