I noticed about a week ago that steam achievements weren't being updated on my Giantbomb profile anymore, I recreated the link and it added over 100 to the total.

Since then I have probably earned another 10 and those haven't updated here either.

Anyone else having this problem?

Yes, I'm having the same problem. None of my new Steam achievements are being synced... :(

I've had this issue for a long time now, and I've always had my Steam profile set to public. I've re-synced my account several times, too.

it doesn't seem to be updating properly, i have to remove then re-add my account to see the new acheivments

Somehow, everyone seems to miss this thread:
Steam achievement syncing offline?