NOTE 1 [file NPT.mdp]: leapfrog does not yet support Nose-Hoover chains, nhchainlength reset to 1

GROMACS version: 2019.4
GROMACS modification: No

I’m simulating a membrane with a solute and I have been using in my simulation tcoupl = nose-hoover and Pcoupl = Parrinello-Rahman and I have received this note:
NOTE 1 [file NPT.mdp]: leapfrog does not yet support Nose-Hoover chains, nhchainlength reset to 1.

I read somewhere that the system may not be ergodic with this condition. Is it true?
What are the implication to reset the nhchainlength to 1?
Is it a benign note?
Thank you in advance.

The are only ergodicity issues with the NH thermostat when the number of degrees of freedom is very small. For a membrane system there is no issue at all.