Does charging in an unheated garage through winter actually hurt the battery long term?

Hi My garage is attached but completely unheated — it sat around -8C most of last winter and the car lives in there overnight. I charge to 80% on a Level 2 unit most nights, usually finishing a couple of hours before I leave in the morning. What I can't work out is whether the pack being cold-soaked for hours after the session ends matters, or whether the only thing that counts is the temperature while current is actually flowing. Half of what I read says preconditioning before charging solves it, the other half says overnight AC charging is slow enough that cold is a non-issue. Has anyone actually seen degradation they could pin on cold-garage charging specifically, as opposed to just slower charge rates in a moment???