Version 2.4.1-3 of libbpp-seq is marked for autoremoval from testing on Thu 19 Sep 2019. It is affected by #925736. The removal of libbpp-seq will also cause the removal of (transitive) reverse dependencies: bppphyview, bppsuite, libbpp-phyl, libbpp-phyl-omics, libbpp-popgen, libbpp-qt, libbpp-raa, libbpp-seq-omics, maffilter, physamp. It depends (transitively) on libbpp-core, affected by #925731.
You should try to prevent the removal by fixing these RC bugs.