There's a closed pull request on the void-packages repository

conky: update to version 1.11.6
https://github.com/void-linux/void-packages/pull/24229

Description:
Conky version 1.11.5 has an annoying bug that displays negative RAM usage:
https://github.com/brndnmtthws/conky/issues/877

This is fixed in release 1.11.6 from 27th July 2020.

My first void contribution, hope this will do the trick ... !