Multiple unknown clients via VPN listed inside another FW Clients list

Hello everyone,

I have an ORG with 3 sites:

siteA- x.x.1.x

siteB- x.x.2.x

siteC- x.x.3.x

I linked them via VPN Site-to-Site.

When I look into Clients of SiteB list I see this:

As you can see I have a huge list of MAC addresses (blu arrows) linked to that firewall via VTI interface (green arrow) having all of them the same IP (red arrow).

Same situation on SiteC:

Is this behaviour expected as properly listed?

As you can see both Clients list are showing IPs from SiteA DHCP list.

Seeing that list like this is not clear because I cannot trace all of those MAC addresses on original site neither on other sites.

Of course I have the evidence of that looking into widgets.

SiteB:

SiteC:

While SiteA is clean as expected: