Bondtype LJ-14 was defined previously

GROMACS version:2021.3
GROMACS modification: Yes/No
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when i was building kalp in Dppc i got error when generating a tpr file stating as below

gmx grompp -f minim.mdp -c dppc128.pdb -p -o dppc.tpr

Ignoring obsolete mdp entry ‘ns_type’

NOTE 1 [file minim.mdp]:
With Verlet lists the optimal nstlist is >= 10, with GPUs >= 20. Note
that with the Verlet scheme, nstlist has no effect on the accuracy of
your simulation.

Setting the LD random seed to -554762787

WARNING 1 [file ffnonbonded.itp, line 1730]:
Bondtype LJ-14 was defined previously (e.g. in the forcefield files), and
has now been defined again. This could happen e.g. if you would use a
self-contained molecule .itp file that duplicates or replaces the
contents of the standard force-field files. You should check the contents
of your files and remove such repetition. If you know you should override
the previous definition, then you could choose to suppress this warning
with -maxwarn.

old: 0.0003314 3.36e-07 0.0003314 3.36e-07
new: OW OW 1 0.0026173456 2.634129e-06

so inorder to solve this issue ,is it ok to delete line 1730 in ffnonbonded.itp file or use maxwarn option to bypass the issue.
i am following tutorial of Justin A lemkul

Thanks in advance

This is because it is already listed under the ffnonbonded.itp file

$ ggrep -n -P "OW\\s+OW" gromos53a6_lipid.ff/ffnonbonded.itp 
1523:      OW       OW  1  0.0026173456  2.634129e-06
3022:      OW    OW     1 3.31400e-04  3.36000e-07

GROMACs could probably have indicated the last time it was used, i.e. file-line traceback. I am assuming they are using a hash for this??