Roblox has updated the Roblox logo a while ago. I would expect the “Roblox Profile” link icon to be updated as well:
(notice the small hole in the Roblox logo. This means it is the 2019 version)
I would not be surprised if the forum used outdated branding in other areas as well.
This is one of the many very small UI inconsistencies I have reported. As such, do not feel the need to support this report, it is just something I have noticed.