Can't find the rule for repeated action attempts

[Immortal Sun]

That is exactly what the rules say. You can't take 20 if there's a penalty for failure (first paragraph), because if you did, then you would be subject to all of those penalties (third paragraph). But penalties need to be played out, which is why there's a hard rule that you can't take 20 in those circumstances.

It is kind of weird that they explicitly tell you that you can't do something, and then speculate on what would happen if you could, but I think they just wanted to be extra clear on what's going on.

Ah, my everlasting issue with D&D: the use of far too many words.

 

[LordEntrails]

Ah, my everlasting issue with D&D: the use of far too many words.

DMG 6E:
Page 1 "Play, Have Fun."
Page 2: credits...

 

[iserith]

DMG 6E:
Page 1 "Play, Have Fun."
Page 2: credits...

And despite its brevity, experienced DMs will still not read it.

 

[Immortal Sun]

And despite its brevity, experienced DMs will still not read it.

Read what?