Who else have got this problem?

You are not alone....it's a bug.
You can try to follow the step in this topic https://www.reddit.com/r/cyberpunkgame/comments/kgnh2c/second_conflict_mission_dum_dum_missing/
I think this is one on the worst bug, because we can't finish a mission.

Having this problem too, and their fix requires you to reload a save right before you meet up with Kerry...I've put in at least 10 hours after that point.

Clearly their QA skipped over a ton of stuff. Apparently this situation depends on how the Militech mission played out for you in the beginning (whether or not you killed Dum Dum and the rest of the Maelstrom gang).

Personally, I let them live and fought alongside them against the small force that Meredith sends. Meaning Dum Dum should def be alive and well, but he's not spawning, but the "skip ahead" still pops up after you encounter the 3 guys in front of that door in Totentanz. And then V responds to nobody. Interestingly enough, if you do skip ahead, you can actually see Dum Dum's model in the glitches produced by the fast forward effect.

Johnny also skips 2 lines of dialogue right when you walk in, but the subtitles still show what he was supposed to say.

Welcome to Cyberpunk, the worst launch in gaming history, have fun lol..