Responsemean error

Dear experts,

When I try to calculate the response function for my cohort, I encounter the following error:

responsemean: Calculating mean RF across 61 inputs, with 4 b-values and lmax=10

responsemean: [ERROR] Unhandled Python exception:
responsemean: [ERROR]   ValueError: math domain error
responsemean: [ERROR] Traceback:
responsemean: [ERROR]   /EBC/local/MRtrix3.0.4/mrtrix3/bin/responsemean:70 (in execute())
responsemean: [ERROR]     log_multiplier += math.log(mean_lzero / subj_lzero)

The command I used is: responsemean response_functions/*_sfwm.txt test.txt

However, if I add the -legacy option, it works perfectly. What is the problem?

Best regards,

Manuel