I didn't create any backlinks for the old site, which was never penalized. I stopped the redirection for about 3 weeks but the change was hard to notice. As for the BOTW listing, the site was penalized on 24 April and got listed in BOTW 2 weeks ago. The traffic dropped with around 30%a after the listing went live. Same happened to the other site which got listed on BOTW, which is not penalized in any way. The 2 sites are not part of the same network, they have different owners, hosting...etc.