How do I do epoxy inlay fills in carvings: workflow, bubbles, and the big gotchas?

The workflow

Carve for epoxy: v-carve or pocket at least ~1/16 to 1/8" deep (deeper = richer color, more forgiving sanding). Flat-depth v-carves and pockets hold color better than knife-edge V bottoms.
SEAL the carve first (critical): brush thin CA, dewaxed shellac, or a thin epoxy skim coat into the carved areas. Unsealed wood outgasses air into your pour = endless bubbles, and dark epoxy wicks into surrounding grain = fuzzy edges.
Mix slow-cure epoxy (deep-pour or tabletop; slow cure sheds bubbles better) with pigment: mica powders, pigment pastes, or tints. Mix thoroughly but gently.
Overfill slightly. Epoxy shrinks/settles, and a slight dome above the surface sands flush. Underfilled letters mean a second pour.
Pop bubbles: pass a torch/heat gun quickly over the surface (seconds; heat thins it and bubbles rise), and repeat over the first hour.
Cure fully (don't rush, because soft epoxy clogs abrasives and smears), then surface flush: either a shallow CNC skim pass (~0.1 to 0.2 mm, and re-zero on the material!) or sand through grits 120 to 220.
Finish the whole piece. Note that epoxy sands cloudy/matte, and the final clear coat (poly/oil) restores its depth and gloss.

Bleed into grain means you skipped sealing (step 2). Worst in open-grain woods (oak).
Bubbles forever means unsealed wood outgassing or fast-cure epoxy in a deep pour.
Cloudy after sanding is normal, and the finish coat fixes it. Cloudy underneath means moisture or a bad mix.
The CNC skim pass beats hand sanding on big fills (flat, fast, no rounded edges), but only after FULL cure.

Tape the board's back/edges, because epoxy finds every path off the workpiece.
Test the pigment ratio on scrap, since colors shift as epoxy cures and again under finish.
Combine with the flattening entry for the river-board/epoxy-slab genre.