@Curly Works great here. When I first installed it, the one on upstairs was randomly slowing/dropping the connection. Turned out it was on the same powerline with a "noisy" LED strip lamp, and when the lamp was turned on, Deco was losing powerline connection. I switched to another outlet and now it works great 7/24, no slowdowns whatsoever.

@Kevin_Z The Deco's are connected to each other. The one downstairs is connected to my router by utp. All the leds are green and the two upstairs even have a green led on the power plug. The powerplug led on the deco directly connected to the router downstairs is orange. 

The wifi receptions is always full bars. It's the internet connection that fluctuates and drops every now and then. I've tried a new setting now, everything is in bridge mode. So the router gives the signal and all the deco's send this throughout the house. But this signal is not stable. I've tried relocating the deco's. Even switched some from up to downstairs and resetting everything. 

It can be that I've got to many devices online, using all the data resource. It can be a foult in the deco mesh setup. It can be anything for I know...

I can't find if it's the providers fault or the deco setup. Only thing I know is that the trouble all started when I installed the deco mesh system...

Right now I'm trying to find out If I really need the mesh setup, and disconnected everything. Just to rule out some things. Trying to find out if it's the router and incomming data signals or if it's the deco system with all its extra's like internet security and childfriendly filters...

Any suggestions?

@Curly 

I’m having the same exact issue on my deco M5. Out of the 3 I have, it only happens to the one in the living room. When I swapped the bedroom unit with living room unit, it remained the same, meaning the bedroom unit that went to the living room stopped working fine. This proves it’s not the HW. I didn’t swap out the power though. Could the power cable have a role? A guy here mentioned he had a “noisy” line and changing the outlet worked for him

@Hashim I've just switched de deco setup from 'router' into 'Access point'. This doesn't give you the 'internet security' and 'parental guidance' but it also does not interfere with the internet data connection. I tried both and with de router settings the internet speed was about 10-20Mbits slower, but with 'the perks'... I think, in my case, that that's the problem - those 'extra's' like partental safety etc. When I tried the Access Point setting, all speed went up and doesn't fluctuate as much. And I've got the speed back. Now I'm looking for a new internet provider that can provide me with more speed, but I didn't knew that it would be this much of a hassle. Looking forward to a new update of TP-Link's firmware for these deco's. Because right now I'm not using them to it's full potentional. Now it's speed an stabiltiy without the perks that TP-Link have promised me... 

@Curly 

Going to try the same now, just switched to access point mode. Thanks for your feedback. Let’s synch up in a few days and share our experience to see if this is the actual solution.