@RyanChen 

Hi Ryan, That doesn't sound possible.  If a channel is manually set and saved there should be no way it would change.  I would suggest making sure you do hit Save and then power cycling the router to ensure the setting takes affect.  If it does and its changing again, try changing your admin credentials and saving the setting once more.   Finally make sure smart connect is not enabled as with Smart connect you cannot change the channel settings.  

@RyanChen 

This is happening to me as well.

After a varying number of hours (sometimes 6, sometimes 24, sometimes 48...) the 5GHz WiFi channel on the router is changed for some reason to 149.

I have the router settings configured to 160MHz Channel Width on Channel 36. This is the configuration that works best for me.

There is deteriotation in the WiFi signal when it auto changes itself to 149. Rebooting the router resets it back to 36. However, after some amount of time it will end up on 149 again.

Possibly a bug in the firmware?

@Carl Yes, I made sure the setting was saved and Smart connect is not on. You may have seen other people already responsed to this post and have the same issue. Another post at https://community.tp-link.com/us/home/forum/topic/195894 have similar issue as well. I think you should perform a test on the AX50/AX3000 with the engineers. 

At the other post your collegue @Tony provided a beta firmware for testing the fixs. However it is for AX3000 not AX50. So I won't be able to test it. I am hoping you do raise the issue to the engineer and make a updated firmware asap. Thank you.

@Kaix unfortunatly channel 36 is quite busy at my place. Let's hope TP-link could provide an update soon. Thanks for posting and get more attention from the forum admins here.

@RyanChen 

hi Ryan,  I had a bit of confusion.  I didn't realize you referring to DFS channels.  With DFS channels the router will do a scan.  If the selected channel is occupied it will renegotiate to a open channel.  Using non-DFS channels and what i said previous is correct.  You will not see the router change.  Its only when trying to use DFS.  

Best Regards

@Carl 

But channel 36 isn't DFS?

@Kaix 

Sorry I was referring to RyanChen's comments.  I missed yours.  I don't have an answer for that.  I engaged with my testing team and they confrimed the infromation i provided DFS channels will auto negotiate but standard channels should not.  I will refer this to the local test team to see if it can be replicated. 

Any progress?

I'll return this router to the store and buy something else if this can't be fixed very soon. Thanks.

Bump

Hundreds (if not more [maybe thousands?]) of customers are affected by this bug.

TP-Link.. what is your plan of action on this one? Do you have one?

Thanks. You have one job... Fix this.

@Carl 

But the thing is that AX50 does not selecte the less interfered channel in DFS group. In fact it always falls back to 149 which in my case it is a pretty busy channel. I can monitor that channel 112 has no other one is using but just could not fixed it to channel 112.

And same issue happends to non DFS channel. I tried channel 48 which is non-DFS channel. Still the router falls back to 149 after a while. Please do some tests and find a fix for this issue.