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B collaborated with Makestar on a crowdfunding project for their next release. The project eventually surpassed its goal, reaching 162% of its funding target. In late October, it was revealed that Sandy, Yuji, and Haeun had auditioned for the survival show The Unit.

However, only Sandy and Yuji passed the initial auditions. Both were eliminated in the first elimination round, ranking 57th and 59th, respectively. The group resumed activities on January 14, 2018, after member Sandy had fully recovered from a hospitalization caused by exhaustion following her participation in The Unit.

In a VLive livestream conducted after her recovery, an upcoming comeback was announced, slated for release in the first half of the year. However, this would be the group's last official activity as a five-member unit. Their next update on social media featured only four members, with Sandy notably absent and presumed to have departed from the group.

In the following months throughout the first half of 2018, Hyunmin also appeared to depart, as subsequent updates and birthday posts only featured Yurim, Yuji, and Haeun. It is presumed that the group disbanded without announcement in late 2018 following the quiet departures of Sandy and Hyunmin, especially as no further updates were provided to their Makestar supporters. The remaining three members, Haeun, Yurim, and Yuji, subsequently redebuted in their agency's new girl group, 3YE.