I'm unable to replicate your experience.

I see this and this , but unless I haven't done enough digging, they deal only with syncing between devices, not between Firefox versions, and my bookmarks and prefs have synced between v 66.0.5 and 67.0 with no required action on my part.

I also had no problem clicking through to an account creation dialog box.

The new Great Equalizer is the SEND button.

In Memory of Harv: Those who can make you believe absurdities can make you commit atrocities. ~Voltaire