Yes, this is very likely going to be true for all future releases unless the build environment is downgraded, or whatever is generating code in the appimage which uses symbols from a libstdc++ release later than the one in Debian 11 et. al. stops doing that (and both those things are most probably Backward Steps in the Overall Scheme Of Things).
It’s not a “bug” in kdenlive introduced by the kdenlive developers, or likely one they can “fix” in kdenlive - it’s an artifact of building the appimage with a newer toolchain.
What is the problem with updating to Debian 12 if you want to use the newest releases of kdenlive? Debian 12 became the current stable release ~5 months ago now, and any regressions with updating to it should be reported to the package(s) concerned there …