Yeah definitely. I've seen numerous individuals hard brick with safesysupdater but that's the nature of the exploit. My girlfriend successfully dissuaded me from downgrading before since she doesn't want to see me brick.
Anyways, her and I are both on 10.3 with menuhax 2.1. Many people have said updating would be relatively harmless, just the destruction of a lot of entry points. After downgrading people get pseudobricks because menuhax had the incorrect payload I believe.
What I am scared of is the same effect while UPDATING. Uninstalling would solve this issue easily, however as many have mentioned this also destroys a valid entry point.
Tl;dr has anyone updated with menuhax and know if your 3DS functions correctly with the outdated 10.3 payload? Thanks for all the responses so far.