Persistant blobs after software update

[stratiegery01]

Hey all,
I did a few upgrades and now there's some serious blob/zit problems on all my prints. I'm running a modified TwoTrees Sapphire with an Afterburner hotend design and direct drive extruder. Before I had my Orca slicer profiles dialed in pretty well for any PLA/PHA material but now no matter what I try, I cannot seem to get rid of them. Here's what changed before I had the blob problems:

1. Swapped my Pasberry Pi-4 running #Klipper to a BTT-Pad7
2. Swapped a hardened steel nozzle to a new 0.5mm brass one
3. Updated Orca Slicer from v1.8 to v2.2

Nothing major changed right?! I kept all my old slicer profiles and of course the printer is the same, so I would expect to be off and printing without issue. Blobs are a common problem though so to fix this I went down a weeks-long root cause analysis but came up short on the 'why'. Here's what I've tried since observing the blob issue:

1. Thinking the PLA filament I was using could be old, I re-ran all the Orca calibration tools to get new baseline values for temperature, retraction, flow, and pressure advance. RESULT: everything seemed normal until I ran retraction. I even reverted every profile to factory-default values before running each test and still I cannot get any indication from the test result as to what the value should be because even at zero retraction, there's no stringing observable. Blobs still persist.
   
2. Thinking there is a data read/write bottleneck in Klipper, I swapped my microSD card running Klipper from a 100mbps Sandisk to a 200mbps Samsung. RESULT: blobs still persist, no observable change.
3. Thinking the BTT-Pad7 was somehow responsible running off their CB1 board instead of a Rasberry Pi, I swapped the printer control back to my old Ras-Pi setup running Klipper. RESULT: blobs still persist, no observable change.
4. Reading similar problems relating to maximum resolution, I tested various prints/models between a range of 0.05<0.4mm. RESULT: blobs still persist, and understandably the higher the resolution maximum, the worse looking prints were.
5. Reading about wipe settings and other quality-related slicer settings, I changed certain values one at a time to see if that made any difference. RESULT: blobs still persist, no observable change.
6. Reading about pressure advance problems, I not only re-ran the Orca calibration test but also played around with the 'smooth time' values in Klipper (as this feature is not present within Orca). RESULT: changing the default value from 0.04s to 0.01s made a positive difference when printing sharp corners; less Z-banding, more dimensional consistency between prints. However, blobs still persist.
7. Thinking there is some other slicer setting I am not able to find through research, I systematically changed retraction and seam settings to see any differences. RESULT: blobs still persist, no observable change.

My last bit of research, and why I'm posting this here, is an similar past issue I found with Cura when they pushed a software update. Based on this Orca Cube calibration print, I think it's safe to say the blobs are most likely related to seam settings (even though I cannot understand why). Another obvious observation is that this is retraction related too, but as described above, changing those settings made no difference.

So.... any thoughts on what I should try next??? (3MF files for slicer attached into ZIP)
blob tests.zip