If connected to SSID 1, SSID 2 signal starts dropping in and out

I also had the iPads dropping off SSID2 - other traffic was on 1.

Buy android, live happy.

Update from DrayTek support today:-

"I've tested this issue and can confirm that if device is connected to
SSID1 on 5GHz spectrum SSID2 is not seen and is not available from
this device unless this wi-fi client is disconnected from SSID1 and then
can re-connected to either SSID1 or SSID2.

During my test, while the wi-fi client had been connected to SSID1, I didn't have any
problem with connecting another wi-fi client to SSID2 and
connecting to the router.
Therefore, SSID2 was broadcast properly, but hadn't been seen by devices already
connected to SSID1 (and vice-versa).

I've been contacted by phone support engineer Pawel who confirmed my
findings.

I'll report this to 3rd line support, so that will be investigated
further and I'll keep you updated."

Has this issue been fixed now? I am having similar problems.

Apparently it's for Mac users and Macs don't support or get confused by MSDA so they can
disable "Aggregation MSDU(A-MSDU)" in >>Wireless LAN>>Advanced Setting

(I haven't tried this myself, just asked!)

I've had a single non-mac device associated and see the exact same problem, with and without "Aggregation MSDU(A-MSDU)" disabled.

So I don't think its that.