Thats normal in repeater bridge mode only one connection is used.
Scenario i used: connected 5g to main router and repeat this on 5 and 2.4g.
Repeater bridge is alwas a little bit freaky, must be the same ssid like host network, encryption must be the same as host network, not auto use wpa2 ccmp (aes) on main and repeater also password has to be the same.
After all this it should work.
But best and stablest way use 5g uplink and repeat only 2.4g
Well, than I use all wrong 
I use dedicated 5G wifi network just for bridging on repeater and on repeater APs with SSIDs same as on main router with roaming enabled. Works perfect. New phones use roaming (I could see they are sometimes connected to both main and repeater) and old devices switches to the strongest network.
Soon I'll go to WDS as I can see it could work - setting repeater "Client WDS" makes new wlanX.sta1 interface on main router wit repeater connected - and thow relayd completely.
Maybe i'm doing something wrong. My scenario is: the main router has 192.168.15.1 range. I wanna put the repeater in another range, like the default 192.168.1.1. I want this because on my main router has an tv connected to him, and on repeater another tv. Sometimes someone cast youtube/netflix videos to wrong tv, separating the networks will avoid this.
I try to connect the uplink to 5ghz (client) network and create 2ghz and 5ghz (master) with different SSID but if the same password, but is very inconsistent. Sometimes work, and sometimes not.
Can i revert back to stock firmware at this time?
In my archer c2 i experience the same inconsistent results.
I'm doing this: in 'interfaces -> lan' i put the gateway of the main router. in 'wireless' i scan the nearby networks (radio0) and connect to the main 5ghz network, at this time i can ping 8.8.8.8 with telnet, so get internet access. Than i create my sub 2/5ghz networks, and i do a lot of configs, with brigde, no bridge interfaces. Maybe i don't understand the concept of interfaces on OWRT, but i try a lot of things and really can't get working flawless.
Make static dhcp leases on main router for all of your devices, disable dhcp on re200, make all nets the same, create a firewall access rule, restrict mac adress of device to mac adress of tv. Voilla
What you try has many disadvatages because of routing trough the nets, can do so but its complicated (for beginners)
n00b/beginner here! 
Nice man! I will try this! The cast problem is one of the problem here. Truly, i wanna separate the main/router from the repeater. This is the reason i wanna OWRT on repeater, because the stock configuration lack this kind of control. But at the same time, the stock is much simple as 'set and forget'. OWRT is much powerful, but 'great power cames with great complexity...' It´s awesome what crap/simple device turns into gold/powerful one.
I'm reading some docs about OWRT to learn how everything work to understand what and how i can do those things.
Thanks!
@phil2sat I'm trying to set up the RE200 as a repeater but have issues with DHCP, described here: DHCP not working on TP-Link RE200 repeater
Do you have hints how to fix that? Did you see a similar issue or does it just work for you?
If anyone is interested I just made a STOCK firmware with just one byte modified in rcS so that the telnet port is open. I think everybody here know the root password...
RE200(EU)_V1_171206 with open telnet
Interesting - what do you need it for if you can install OpenWrt via the web interface?
just to make tests with the original firmware.
Granted, it's easier than opening the case and attaching serial console 
question: for testing, I uploaded using tftp busybox-mips in /tmp
but it does not seem to work.
any clues?
another interesting thing is the shellc ommand flash which operates on the ralink internal spi-flash I think that is the key to enable/modify the maximum txpower level of wifi. I will dig it more.
Just for update, i got my Archer c2
(kind of topic) working fine repeating the signal connected to my router with 5g and create 2g access point with different ip range like i want, and this is enough to separate clients, so no cast to wrong tv anymore. At this point it solve my problem, and i do this for testing purpose to check the stability, and for now it working very good. Next week i will do with RE200.
Thank you so much for your help!
After installing the latest snapshot, I ran into the issue described in Jffs2 partition not save new package installation or save settings. Building firmware myself from commit 8df14c229c02a3b9329afc6e3ebf4f8aec5b59ed and installing it solved the problem.
Hello, i made openwrt image from windows without luci, now i finded openwrt with luci. How to update from openwrt to openwrt?
how to flash it from openwrt without luci
or how back to stock, only via TTL? Please help me
How to flash from command line: https://openwrt.org/docs/guide-user/installation/sysupgrade.cli
Alternatively: install luci from command line:
opkg update
opkg install luci
How you would flash via TTL if you can't find the upgrade from cli procedure in the wiki by googling - no idea...
@andyboeh Is there a roadmap / todo list for getting a stable release for the re200? Or will it happen automatically now, once the next release is made?
It's in trunk, so it will get a stable release automatically once a new OpenWrt release is out. That's how OpenWrt releases work.