use --evaltrace to see which resources are evaluated. Maybe this gives
you a hint what's happening.
Since you seem to be pretty sure this is not a problem rooted in the
machine itself, the attentions focuses on the environment: Perhaps there
is an IP-collision with another device on the network? Perhaps the
switchport is faulty? The underlying virtualisation has something fishy
configured? The nameserver is acting up? etc.
Good hunting, D.