"auto-negotiation on speed" and "link-speed" are different

[BlueGrass]

Dear All,

My 1G ISP is connected to eth1.

Then we find the speed test result is slow.

The show interfaces all Appears below result:

Interface eth1
state on
mac-addr XXXXXX
type ethernet
link-state link up
mtu 1500
auto-negotiation on
speed 1000M
ipv6-autoconfig Not configured
duplex full
monitor-mode off
link-speed 100M/full
comments Sonicwallx1_Wan
ipv4-address XXXXXX
ipv6-address Not Configured
ipv6-local-link-address Not Configured

Why this is happening with both speeds different?