Hello,

I repost bug here because there is no new reply from tplink team in this thread (proof that I'm not the only one to see this bug) : https://community.tp-link.com/en/business/forum/topic/816266

The ISP load is abnormaly 1ms flat on the firmware 2.2.0 of the ER7206 in auto or manual "echo server". I first noticed it in january.

First : I purchased the ER7206 on december 2024. It was delivered with firmware 2.1.2 and the latency was fine (not 1ms flat).
On January 2025 I upgraded to early 2.2.0 to test "DNS LAN" (which is not a local hostname resolution now I mention it and useless in my useccase, I was serching for client names resolution) and perfomance optimizations.

Just after the the upgrade : I noticed that ISP load showed a 1ms flat graph (I didn't  reported it because I thought a patch will come soon but you don't seem to know it).

As proof : I downgraded my ER7206 to 2.1.2 few hours today to show you it's firmware 2.2.0 the problem.
In 2.2.0 latency was 1ms flat. After downgrade, latency seemed well fluctuing behind 10ms. After reupgrading to 2.2.0, flat 1ms latency is back
 

Approximative time of downgrade on v2.1.2 firmware : 5h30m

Results on ISP Load :

Results on perfs (for information) :

Zoomed :