I recently started putting my succulents on a south-facing window sill for the past month. It only receives about 2-4 hours of direct sunlight per day and it hasn't been very hot.

However, one of my succulents that used to look like this (ID please?): {{gwi:607316}}

Now looks like this:
{{gwi:607317}}

I did do a few other things to it such as pull the dried up leaves around its roots off, add more soil to cover the roots. It does not seem to have root rot.

A similar thing is happening to my other succulent (ID please?)
{{gwi:607318}}

It has leaves that look like this:
{{gwi:607319}}

I noticed that the leaves facing the sun are more prone to getting wrinkled... but it only started doing this within this past week... whereas I've been putting them on the window sill for the past month. Does anyone know why this is happening? Is this what the beginnings of sunburn look like?