ES-9 — fixed ~76 ms recording latency in Bitwig that doesn't change with buffer size (macOS)

[dmuirw]

I have an Apollo twin to ES-9 aggregate device with drift correction on on the ES-9 and Ive done the Aggregate device flipped around also ES-9 to Apollo etc. and nothing is working to fix the Latency. Ive also tried the WES-9 by itself and still no way to fix the latency. I've used Silent way and HW Clock plugin Bitwig.-Nothing

Problem in one line: Recorded audio from the ES-9 lands a fixed ~76 ms (0.076 s) behind Bitwig's grid, and the lag does not change when I change the buffer size. Bitwig's Recording Offset caps at 2048 samples (~43 ms), so it can't compensate the full amount.
System:

MacBook Air, [16 gb. M1], macOS [Seq 15.7.5]
Bitwig Studio [6.1]
Expert Sleepers ES-9 (class-compliant USB on macOS), firmware [latest]
UA Apollo Twin [apollo Twin/ X ], run together with the ES-9 as a macOS Aggregate Device
Clock to modular via Bitwig HW Clock Out → ES-9 → ALM Pamela's PRO Workout (24 PPQN) + WMD Metron. The clock works perfectly — this is only about recorded-audio alignment.

How I measure it:

Loopback: ES-9 output → ES-9 input with a patch cable, play a sharp click on beat 1, record it back, measure where it lands. Result: ~0.069–0.076 s late.
Real-world: a modular voice clocked by Bitwig, recorded against a Bitwig kick on the grid. The modular lands 0.076 s behind, measured transient-to-transient.

The key anomaly — it's fixed across buffer sizes:

512 samples → ~0.069–0.076 s
256 samples → ~0.076 s
128 samples → ~0.076 s (identical; a 4× buffer reduction changed nothing)

Real I/O latency should scale with the buffer. Mine doesn't move at all.
Already tested and ruled out:

Aggregate device order (ES-9 first vs Apollo first): no change
ES-9 alone, no aggregate: same ~0.069 s
Drift correction off: no change
Both devices confirmed at 48 kHz: no change
"Audio Recording Latency Compensation" is ON
Record track, click track, and master bus all empty (no plugins / no PDC): no change
Clock is via the HW Clock Out device (not HW CV Out, not a Grid CV Out patch)
Recording onto a plain audio track (not a CV In module)
Recording Offset maxes at 2048 samples (~43 ms) — can't reach the ~76 ms

Constraint: I need to run the ES-9 + Apollo Twin as an aggregate, because the Apollo handles my monitor outputs and vocal/instrument tracking. So ES-9-only isn't a usable permanent setup.
Questions:

Why is the ES-9's record latency a fixed ~76 ms that ignores the buffer size? Is the macOS generic USB driver under-reporting the ES-9's true latency to Bitwig, so it can't auto-compensate?
Is there a fix — a config/firmware/CoreAudio/aggregate setting — that either reduces the underlying latency or makes it report correctly so recordings land on the grid automatically?
If not, is there a recommended routing or workflow for this exact ES-9 + aggregate + macOS situation?

[BobDog]

if the ES-9 when used alone is giving you 69ms then I would start looking there first, it seems a huge amount.