I found the bug report: https://bugs.kde.org/show_bug.cgi?id=482628
As a workaround, I renamed Find in toolbar to Search. Which removes Alt+f to Konsole and sends it to the shell.
After Plasma 6, Alt+f invokes Find, instead of forward word, and it's driving me nuts. I can't seem to find any shortcut to stop this. Konsole shortcuts show Ctrl+Shift+F for Find.
I found the bug report: https://bugs.kde.org/show_bug.cgi?id=482628
As a workaround, I renamed Find in toolbar to Search. Which removes Alt+f to Konsole and sends it to the shell.