This only happens upon initial import of photos:
1. Import photos with metadata presets
2. The preset metadata appears in the metadata browser
3. Update additonal metadata fields manually and they do not update real time in the metadata browser
4. Quit LR and relaunch
5. LR gets hung up updating the metadata browser
6. Now the metadata set manually appears in the metadata browser
7. additional metadata browser fields can be updated real time
I spoke with Dan Tull and apparantly they have seen this problem however it cannot be specifically identified. His email response back to me was as follows:
"A few people internally have occasionally spotted this issue, but it tends to disappear right about the time we try to file a bug about it. Does it happen if you change photos individually? The times it happened to me were cases where I was doing relatively large bulk edit operations."
It happens to me either individually or in bulk.
I am waiting to hear back.

