Gabor filter 'not vanishing fast enough'

[EoghanTotten]

Hi,
Getting following error below. Only modification of my inparams was to change the kernel SPP from 4 to 8 for my AxiSEM wavefield (parameters otherwise unchanged!).

ERROR: Filter Gabor_20 is not vanishing fast enough for
high frequencies.
Numerical noise from frequencies above mesh limit will be propagated
into the kernels. Check the files
filterresponse*
filterresponse_stf_*
Relative value of forward TF at half mesh period : 0.35443443457184026
Relative value of backward TF at half mesh period : 0.40594410662365144
Cutoff period: 3.5677747662280885

Modifying the sigmaIFC from default 0.5 does not help, whether raised or lowered, nor using higher or lower frequency filters. Any ideas? @sstaehler @kasra-hosseini @harriet-godwin