Can you please explain this? This type of thing has happened to me multiple times over the last few months, since I think, adding XE750 pro to the mix

TP-Link Camera on IP 192.168.2.59 is using Wifi

I have these DECO's

PC connected to ServerRoom6e 

C:\Users\Administrator>ping 192.168.2.59

Pinging 192.168.2.59 with 32 bytes of data:
Reply from 192.168.2.59: bytes=32 time=15ms TTL=64
Reply from 192.168.2.59: bytes=32 time=2ms TTL=64
Reply from 192.168.2.59: bytes=32 time=2ms TTL=64
Reply from 192.168.2.59: bytes=32 time=14ms TTL=64

Ping statistics for 192.168.2.59:
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
    Minimum = 2ms, Maximum = 15ms, Average = 8ms

C:\Users\Administrator>tracert 192.168.2.59

Tracing route to 192.168.2.59 over a maximum of 30 hops

  1     4 ms     2 ms     4 ms  192.168.2.59

Trace complete.

C:\Users\Administrator>

So, fine.

PC connected to 'Study' deco

C:\Users\Paulhome>ping 192.168.2.59

Pinging 192.168.2.59 with 32 bytes of data:
Reply from 192.168.2.100: Destination host unreachable.
Reply from 192.168.2.100: Destination host unreachable.
Request timed out.
Reply from 192.168.2.100: Destination host unreachable.

Ping statistics for 192.168.2.59:
    Packets: Sent = 4, Received = 3, Lost = 1 (25% loss),

C:\Users\Paulhome>tracert 192.168.2.59

Tracing route to 192.168.2.59 over a maximum of 30 hops

  1     *     Paulhome-PC.lan [192.168.2.100]  reports: Destination host unreachable.

Trace complete.

Yet same PC connected to study deco has full internet access etc. It is just this IP (and sometimes some other TPLink cameras) that becomes unreachable from some DECO's only, and it is intermittent.

Here is the network map. PC in both cases are connected to the Ethernet of the DECO, not wirelessly. Study uses an ethernet backbone to reach Serverroom6e