Wifi very slow unless I cycle airplane mode on/off

[claykin]

Same issue with my S8 and now this S9+. I return home, connect to wifi and phone data is crazy slow. If I cycle wifi off/on, I have same issue. If I cycle airplane mode on/off wifi speed returns to normal. This occurs every single time I enter my home.

Access point is not the issue because I've tried two different products. I make sure airtime fairness is disabled. Doesn't help. Any ideas.

AP tried:
Netgear R7000 in AP mode. Using both netgear firmware and Merlin firmware. Same issue.

Ubiquiti AC Pro. Latest firmware.

 

[TwitchyPuppy]

Have you tried selecting a different channel, in your modem setup?

And does it occur on 2.4 and 5 Ghz?
Do other people also have this issue?

 

[claykin]

Using 2.4Ghz due to range. Wifi load is light. Yes, tried changing channel, also tried reducing to 20Mhz only. Other devices all work ok. No issues. Only the 2 Samsung phones. BTW, it's not an Oreo issue. The S8 had same issue with Nougat.