I'm having the same bug with Lae'zel. Not sure what triggered it. I think she stopped following after i rested after the vision cutscene at the goblin camp. Seriously ruining my run.
Hurrah! This seems to have been successfully fixed in the hotfix that has just dropped. I had savegames both where Lae’zel had already stopped following and where she’d reliably stop following on the next rest, and in both cases she now keeps up with the party.
Looking forward to finishing my drow bard playthrough that I’d set aside due to this bug. But I’ve now grown attached to my deep gnome rogue … choices, choices!