LinkedIn doesn't show dates for profile photos, but I know from looking her up over the years that her previous photo from earlier this year more closely resembled her younger 2010's photos (of course, her hair was tied back because of her profession).

Her most recent activity on LinkedIn was 5~6 months ago, in which she announced that she had received a certification for a new technical skill. Often people update their profiles when they've had a significant career achievement or change.

Yeah, there have been rumors over the past few years about her cutting her hair, but no reliable sources to confirm this. Someone on Pinterest even posted a poorly photoshopped version of her holding her "cut" ponytails, when really it was one of her old gallery photos where she was just displaying her (uncut) hair.

Marianne's her is/was my ideal hair for my future partner - natural European brunette, knee-length, medium to thick hair, slight waves with a bit of a texture, perfect for braids and buns.

Some years ago someone shared their amazing-hair.de account and password, and I downloaded one of Marianne's videos where she was taking down her braided bun in her bathroom. Definitely one of my favorite long hair videos, although sadly cloud storage was in its infancy back then and so I never thought to archive it for safekeeping.

I think it's very unlikely she cut her hair because of her job, given that she was already well-established as a PhD, postdoc and data analyst around the time she was most actively posting on her website. There was an old TV interview on YouTube where her partner at the time also seemed very appreciative/supportive of her long hair.