TP-Link RE350 unable to connect to Archer C7 v2

My wireless extender: TP-Link RE350 running v18.06.2 (not supported after this version)
My router: TP-Link Archer C v2, running v18.06.5 (still supported ie. 19.7.4)

The RE350 won't connect to the Archer C7 v2 running OpenWRT if I install any version from v18.06.6 and above on it. The RE350 works fine when the router runs on 18.6.05.

It seems that from v18.06.6 onwards, BSSIDs are handled a little differently. I found this on the v18.06.6 release notes for the Archer C7 v2:

This is at least for Archer C7 v2. The default bssids for the networks in my particular device are:

:::::*D for the 2,4 GHz radio and
:::::*C for the 5 GHz radio

In LEDE they result in

:::::*C for the 2,4 GHz radio and
:::::*B for the 5 GHz radio

The problem in LEDE is that the bssid set up for the 2,4 GHz is the one for 5 GHz and then the 5 GHz gets minus one.....etc

Unfortunately, since RE350 is connected to a CCTV and works perfectly, I rather not mess around with the extender's setup at all.

My question is: What changes could I make on the router running a newer version of OpenWRT and still get it to work again with the extender.

Thank You.