folded structure is not the same size of the input sequence and differs significantly from mfold prediction

[ita-infiniplex]

For example:

from seqfold import fold, dot_bracket, dg 
seq = 'AAAAAAAAAAAGGCCCCCTCTCTTGC'   
structure = dot_bracket(fold(seq))                    
energy = dg(seq) 
len(seq) != len(structure)            # 26 != 19
structure == '..........(((...)))'
energy == 0.4

RNAFold structure: with dG: -0.95

and mfold structure: with dG: -0.27

Am I using it wrong or is something off here?

Thanks!