Anodized Aluminum Particles

A. We really need more information. Meanwhile, high heat will crack it off. High pressure will crack it off. If the parts were mechanically finished before anodizing, then maybe, iron media dust is embedded then bridged over by the oxide, then cracking off under either heat and/or pressure. Inadequate cleaning and/or deoxidation before anodizing would be bridged over and crack off later under service.

What is the alloy, thickness of anodizing, service requirements, cleaning cycle, mechanical pre-treatment?

A. Sounds to me like the anodize coating is being slightly crushed from use and is breaking up into fine particles.

Taber Abrasion Tester

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Alloy? Organic or two-step dye? Cleaner? Thermal cycling, perhaps with steam? Is the surface easily abraded? Is the remaining surface (beneath the lost particles) still black? Any Type II salt spray and Type III Taber test results for anodize of the same vintage, on the same alloy? Also, any salt spray test results for sealed Type III per MIL-A-8625F, Amendment 1?

W/o examination or additional info, basically a guess. If no evidence of mechanical damage, chemical attack or overheating (such as loss of color), it is reasonable to presume an anodize problem.
The outer hard anodize was perhaps crumbly (as from inadequate agitation/cooling) and further softened by dyeing & sealing. Black color remaining under lost material is consistent with crumbly anodize, readily penetrated by dye. Crumbly anodize may have slowly swelled from the cleaner (or steam sterilization?) and is now shedding under touch.