In the אֽוֹלִיכֵם֙ of Jeremiah 31:9, translated as "I will make them walk by brooks of water" (ESV), the pronominal suffix after "make them walk" sure looks like a second person masculine plural, not a third person MP. Should it not be translated as "I will make YOU walk?" It is kaf tsere mem, not he tsere mem.
The kaf is the third radical (i.e., part of the root), not part of the suffix.
The word of interest is
אֽוֹלִיכֵם. This is a hifil imperfect first common singular* from הלך with a third masculine plural suffix, tsere-mem. (The he is not generally part of the 3mp suffix on imperfect forms.) The un-suffixed form ends in a kaf:
I will make them walk is a good translation.
*Inflected, characteristically, as if I-yod, i.e. I-waw -- see linked paradigms.