Bitdefender updated engine at 7:22 AM Pacific time according to Product Information in About. After 8 am, I noticed that the computer case fans were running at high speed. Normally I can't even hear my case fans except when an AV scan is running and even then it is not as loud as today.
In Task Manager, one bdservicehost was using up to 58% of my CPU (AMD 7-5800X), 50% Disk usage (Samsung 980 Pro 1 TB NVMe) and 23% of my 32 GB memory. A scheduled scan had run about an hour earlier, but no scans were now running. I went into Bitdefender settings and set Bitdefender Shield to off, but that made no difference in cpu/memory or Disk usage.
Turning off the computer and leaving it off for about 30 minutes, then turning it back on and all is now normal operation. I did note that almost immediately after computer restart, Bitdefender downloaded a new update: heurinc.exc per the log.
Hope this is the end of this problem.