Bug reports have often been opened and marked as solved, but the problem keeps coming up.
https://kde-bugs-dist.kde.narkive.com/p0LyAAHx/konsole-bug-351231-new-all-profile-settings-get-lost-after-exit-no-configuration-files-written
https://bugs.kde.org/show_bug.cgi?id=380518
https://bugs.kde.org/show_bug.cgi?id=433210