I also had recurring problems with third rail continuity because of defective welds of the contact tabs. My fear was that inaccessible tracks in tunnels and or under the city platform would fail and ruin my layout. So as my layout was already built, I opted to solder brass strips across the 3rd rail joints. Since adding the brass strips, the 300+ feet of Real Trax on my layout has been excellent.
I too only use the solid rail Real Trax, but I find that the weld problem is not unique to any one batch of Real Trax. Your fix is the way to for any new tracks I install. Thanks for sharing it.