Especially noticeable when the tinted blocks contain a lot of model geometry (e.g. fences).

Red spike when placing a block in a chunk section with Colormatic tinted fences.

Known properties

• Affects chunk sections which contain blocks tinted with Colormatic; the more geometry the worse the spikes
  • The Colormatic tint must be pure white (-1)
• Lag scales with biome blend radius (no blending results in no lag)
• Must have both Sodium and Colormatic to reproduce
• Lag spikes on chunk section update (block/lighting update that affects the section)
• The initial render of affected chunk sections is similarly delayed (tho this doesn't lag the client)

Sodium treats -1 / ffffff as meaning "do not cache"; this is the cause of the issue.