problem with labeled TRS: labeled rule .. missing

output/2025-08-10/s6/60/SRS_Relative/Waldmann_23/size-10-alpha-2-num-58.ari.ceta

1: error below flat context closure
1.1: error below the sem.lab technique
1.1.1: error below the splitting
1.1.1.1: error below flat context closure
1.1.1.1.1: error when applying semantic labelling on 
rules:
...
a[[0]](a[[0]](x)) ->= a[[0]](a[[0]](a[[0]](a[[1]](b[[1]](b[[0]](a[[0]](x)))))))

problem with labeled TRS:
labeled rule b[[1]][[3]](b[[1]][[3]](b[[1]][[3]](b[[1]][[2]](b[[0]][[0]](a[[0]][[0]](x)))))) -> b[[1]][[3]](b[[1]][[2]](b[[0]][[0]](x))) missing