IPTC confusion between LR and Bridge

Hello, Everyone...

I've also posted a copy of this question on the "LR" section of the forum...

I'm busy doing my 'bulk metadata' entries on many years of photos, and have noticed something that confuses me. All the work I'm doing on IPTC metadata in LR is working great. Many nice features and controls. But, as I understand it, when I change the metadata of various files in the IPTC fields, this 'new' data is written to those IPTC fields and NOT ONLY to the LR catalog.

So why can't Bridge 'see' any of those changes? When I use Bridge to check out some of the files I've been working on in LR (and by 'working on,' I mean entering various things in the IPTC fields), it doesn't show up in the IPTC part of Bridge's 'metadata' browser.

I do notice that the IPTC metadata fields in LR are just called "IPTC," and in Bridge they seem to be called, "IPTC Core." Does this have anything to do with why my LR IPTC changes don't show up in Bridge? In LR, am I writing to some other part of "IPTC" that Bridge doesn't 'see'?

Or does this have something to do with my confusion concerning how LR uses this 'new" IPTC data I'm entering. Is this new data ONLY going into the LR catalog, and not really into the IPTC data that's embedded in the file?

As usual, sorry for the long explanation of my problem. I can't seem to help it...

Many thanks.

Robert