Is there anything unusual about the monitor? For example, adapters or a KVM?
FYI, a monitor is queried for its specs via an i2c protocol. The i2c itself is powered through the HDMI on the Jetson, and so regardless of having the monitor on or off this should succeed. I am wondering if the i2c/DDC wire is doing something odd at power on (which in turn something like a KVM could affect).