Bubbles/Pits on H2D with PETG Translucent only?

Bambu Lab H2 Series
1

I’m having a persistent issue with my H2D printing translucent PETG and I’ve been unable to isolate the cause. I’ve tested Bambu PETG Translucent and other brands, all fully dried, across different speeds, temperatures, and nozzle sizes, but the H2D still produces the same bubble or pitting defect.

To rule out filament, I ran back to back prints of a simple cube using the exact same spool on another printer, which printed to expectation. At this point it seems specific to the H2D rather than the filament. Has anyone seen this before or have ideas on what machine side issue could cause it?

H2D Test with 0.8mm nozzle:

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A1 Mini with 0.8mm nozzle printed with excellent quality.

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Also kind of an aside, is there a reason why Bambu Studio notes a 0.6mm nozzle even though I have the printer set to 0.8mm?

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2

I can’t believe I missed this, but it appears the retraction length on a 0.8mm setting is 3mm by default, which by my estimation is pumping air bubbles into the material. I changed the settings as per below with some changes for cooling on the filament profile, and the resulting print quality was excellent.

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H2D 0.8mm Post changes result:

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