I had this problem earlier this year (when I first tried to use reduce overlap), amongst other issues.
I was using:
AMD FX-8350, 32GB ram, SSD
2x Nvidia GTX760 4GB (with driver version 388.71)
Windows 8.1 Pro
The graphics cards are right old now, I downloaded driver 388.71 in January 2018, that was the last driver version that cuda worked on for these cards. when cuda doesn't work metashape either can't see the cards properly or throws up errors all the time. That driver only had cuda support to v9.0
In April 2020 I upgraded to 1x Nvidia RTX2060 6GB (latest drivers) & reluctantly to Windows 10 Pro and not had the problem since with reduce overlap -> empty bbox.
I'm normally using the latest stable version of Metashape (not preview releases) Standard.