Diagnosis
This is often caused by "roaming" or band steering where the system tries to move your device between nodes or bands, but does it poorly, causing a brief dropout.
How to Fix It
Let's try adjusting the roaming sensitivity. 1) Access the web interface at router.asus.com. 2) Go to Wireless -> Professional. 3) Find the Roaming assistant setting. 4) Lower the RSSI threshold value (try -60 dBm or -65 dBm). This makes the system less aggressive about kicking your device off, which can reduce unwanted hops and drops.
If That Didn't Work
There might be interference from other devices. In the same Professional menu, try changing the Control Channel for both your 2.4GHz and 5GHz networks (use the dropdowns). Start with channels 1, 6, or 11 for 2.4GHz, and a higher channel like 149 for 5GHz.
Heads Up
Some older devices (smart TVs, IoT gadgets) have terrible roaming logic themselves. If the problem is only on one specific device, the blame might lie there, not the ZenWiFi.