On SWV e-visa but passport got stamped (not first entry)

Hi everyone, I’m hoping to get some clarity on whether this is normal procedure.

I was out of the UK for a week on a business trip. When I arrived back at Heathrow, the immigration officer asked the usual questions and then stamped my passport with the date of entry. This caught me off guard because, since my first entry into the UK, my passport has never been stamped on arrival before.

For context, I’m an Indian passport holder on a Skilled Worker visa.

Has anyone else experienced this, or know if this is standard practice? Any insight would be really appreciated.