A very brief but hardly comprehensive overview of RCA's dynaflex vinyl: https://en.wikipedia.org/wiki/Dynaflex_(RCA)
Interesting to note that other major record companies were re~utilizing vinyl at the time and note that a lot of 'audiophiles' complained that Dynaflex sometimes resulted in bass loss.
Also note that Dynaflex pressings extended into the late 70's which would theoretically cover the entirety of the CD~4 era.:yikes
I don't have a problem with Dynaflex in and of itself, I know it has its detractors, they do feel flimsy by definition which might contribute to getting more easily warped and all that entails.. but I have a number of excellent sounding Stereo Dynaflex records I enjoyed long before I went down the Quad LP road, so I don't think that is the problem with my own personal experience with RCA CD-4 records distorting left, right and rear right.. I think (just a hunch) that when you look at the way the American RCA CD-4 discs are cut which is unlike the Warner, Motown, etc (pretty much everyone else doing CD-4) they are a bit more like regular LPs with wider bands for each track and smaller run out grooves.