I'd say ashwalen didn't work on Ichigo either because:
1). He's transcendent. In the sense that he was always a conglomerate of souls so ywach couldn't directly interact with him.
2.) His Quincy powers were hidden at the time so there was nothing to take.
3.) Maybe Ywach never tried to take his powers in the first place because he wasn't a Quincy. A Quincy soul is supposedly different from the other types (just like shinigami, hollow are also different from others), so perhaps Ashwalen only works on Quincy (whether pure or impure)
4.) Alternatively, ichigo might have been protected from something that could range from either White, His inner Ywach, Urahara, Masaki or Isshin's or perhaps all or an addition of one or two of the above.
Although ywach knew Ichigo was Quincy so its either he didn't try to take his powers or he couldn't. Basically.
Currently, I don't think there's enough info to judge which reason is right. All in due time I guess. Or maybe not.
1). He's transcendent. In the sense that he was always a conglomerate of souls so ywach couldn't directly interact with him.
2.) His Quincy powers were hidden at the time so there was nothing to take.
3.) Maybe Ywach never tried to take his powers in the first place because he wasn't a Quincy. A Quincy soul is supposedly different from the other types (just like shinigami, hollow are also different from others), so perhaps Ashwalen only works on Quincy (whether pure or impure)
4.) Alternatively, ichigo might have been protected from something that could range from either White, His inner Ywach, Urahara, Masaki or Isshin's or perhaps all or an addition of one or two of the above.
Although ywach knew Ichigo was Quincy so its either he didn't try to take his powers or he couldn't. Basically.
Currently, I don't think there's enough info to judge which reason is right. All in due time I guess. Or maybe not.