Curious about RSTP's message age.

Hi Experts!

I'm currently study about RSTP and i have read that the Root switch will set the message age in BPDU = 0, all down stream switch will increase the message age value by 1, if the message age equal max age, BPDU will be invalid and devices not all switches will know about topology change.

I made a simple lab below in VIRL:

Sw1--------G0/1----------Sw2--------------G0/2------------Sw3

Switch 1 is the root, all switch run RSTP.

Here's My understand:Switch 1 will send BPDU with Message age = 0 at f0/1.

My verification:

Sw1 :

Port 2 (GigabitEthernet0/1) of VLAN0001 is designated forwarding

Timers: message age 0, forward delay 0, hold 0

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Switch 2 will send BPDU with message age = 1 at f0/2, But...

Sw2:

Port 2 (GigabitEthernet0/1) of VLAN0001 is root forwarding

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Timers: message age 16, forward delay 0, hold 0

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Port 3 (GigabitEthernet0/2) of VLAN0001 is designated forwarding

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Timers: message age 0, forward delay 0, hold 0

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The Msg age in Port 3 is 0, absolutely is wrong. but when i do packet capture it's right:https://imgur.com/a/bLAUNUk

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But why Sw2's port 2 (g0/1) has the msg age of 16? Also the information display on Port 3 is incorrect, anyone knows why or Virl is having some issue? Thanks...