Have seen a few YouTube vids on this (so now i am an expert).
Seems the dominant opinion is that it probably won't hurt the mag spring or mag housing unless they are poorly made.
Yet, most also recommend emptying the magazines so that each gets some empty time. Emptying could be either use at the range or manually unloading and the re-loading them. Personally, I doubt this makes much difference...a good mag should be ok for a year or so.
With all that said, I keep my Sig P365 mags loaded a round short of capacity because they are so tight when topped off. But that is just me, Sig hopefully designed them to be reliable when topped off.
Almost no one I have heard preaches doom and gloom about leaving mags loaded for a reasonable amount of time (year or so).