Some meter do have clicking relays when they start, the input Kinda place itself for the needed measurements functions ... DO the measurements work okay ?? DO you have some problems with the meter ?
But some K2001 user(s) can or could answer you, be patient
If you need them
https://www.ebay.com/itm/353249936558It depend how the relays is made Ex: some of them are reed switches, some are mechanical contacts ... you could have some wear over time, oxidation in some case with unsealed casings ...
For an example, at my work some relays develop an non infinite conductance between the contacts pins, meaning it affect one detection circuit on a pcb, if you measure the normally open contacts we have some 20 to 30 mega ohms of impedance, not infinite as we should have
Pop a new one (tested) and it's okay