For now I cannot reproduce reported bug.
I tried to create druadan rogue and telepathy works as it expected.
Moreover, my current character is druadan priest and in this case telepathy works fine too.

Please, provide more information about your problematic run (save file would be nice too).
Which version are yout playing? What type of dungeon (Standard WIlderness, Extended, Hybrid Dungeon or Angband Dungeon), etc

That's interesting.

Standard wilderness. In this level you can 'd'etect a dragon and an imp. The persons are always visible. Try the M command

Thanks, confirmed, bug filed.

Fixed version now on the release page. I'll try and actually get 2.0.1 out in the next few days.

Sorry, didn't catch that you meant across the entire level.

Is this still happening? It seems to be working OK in my brief testing.