OS X V10.6 Snow Leopard :: Time Machine Exhibiting Several Odd Behaviors, Not Working Properly?

I recently had my HDD replaced after a failure, and reinstalled 10.6.8 using Carbon Copy Cloner. The new drive came from Apple, and had 10.5.8 pre-installed (the OS that my late 2008 MBP came with), but CCC did what seemed to me to be an excellent job restoring. The clone was right at about two weeks prior to the old HDD failure, so once I cloned over, I only had to sync up with Dropbox, and manually move a handful of files (really from just a couple of folders for work) for things to be just as they were leading up to the failure. Here's what's happened (roughly) over the past week with TM:

1. Slow backups. Slow as in 1-2 KB/minute. This all starts with TM "calculating changes" which means about 20 minutes of crawling through and re-indexing(?) directories to look for changes. This happens each time.

2. Backups come in successive pairs. Time Machine Buddy shows this. One backup ends, having copied ~277,000 files (not a typo), then a second one begins immediately after, copies ~255,000 files (also not a typo), then either thins and/or deletes expired files.

3. #2 happens over the course of 2 1/2 hours, reliably.

4. After #2, the next backup comes about 2 hours later, starting all over again. Mere KB take the full 2 1/2 hours.

5. After each of the last backups, I have MORE space reported as available on the external drive. It seems to randomly delete backups from roughly 1 month ago.  

Here's what I have tried:

1. Delete the TM prefs file in my user folder (not /)

2. Repaired the disk - things were very screwed up, with links needing repair all over the place. Thought this would solve things, but it didn't.

3. Hid the external from Spotlight's indexing

4. Deleted backups (via the TM interface -> "delete backups" option, NOT manually) after disk repair, in the event/hopes that initial backups following the new HDD replacement were bad.

5. Repaired permissions, etc.

6. Console doesn't throw what appear to be any errors. Just shows the successive backups mentioned above, the hundreds of thousands of files copied, and that TM deleted something each time.  

Info:
MacBook Pro, Mac OS X (10.6.8)