Bill had a brand new 100/400 and I had one that i purchased when they first arrived. Some months ago. A fabulous lens. Sharp with great contrast. All in a small size for the mm and performance.
I've heard that lens brings out this type of problem in the Z9, but it's not exclusive to it. Could be firmware in the lens. Could be overheating. All of the "I've never heard it happening" bullshit on this thread is inconsistent with the dozens or so threads on Dpreview talking about the same problem, with the only solution being a motherboard replacement. People sending in cameras to NPS are getting them back DOA with the same problem.
One example:
"Just got my Z9 back from repair at NPS today, when checking and loading in my settings, the camera will error if I'm in the video mode, and hit the + key to zoom in and check focus. Is this a known bug? I can't find anything online.
Z9 went into repair for a motherboard replacement. Camera would lock up and crash after about 15 minutes of shooting.
This makes digital medium format look reliable..
EDIT: Does it in photo mode too now..
EDIT 2: Camera now errors out and crashes when I try to take a photo, with or without cards. Reset the settings, no changes, crashes when I try to zoom in or shoot a photo.
Edit 3: Camera seems to shoot a picture if I have the body cap on, and at less than 1/4 second shutter speed.
Looks like it's back to NPS again...
Takes the cake for the most unreliable camera I've ever used, and I've used Hasselblad digital backs.."