TFS is likely getting same part as others.
Water and other damage then the mirror is likely not made right, have polluted water on them and/or are using paper towels or other abrasive cleaning.
Most Paper towels tissues etc are very bad to many mirrors, glasses and lenses, worse when the parts are coated for anti glare etc.
Many External mirrors hate Many "soaps" to wash cars too.
"Standard" mirrors for most things is 2nd Surface mirroring or IOW back coat mirroring. This is "cheap" and "easier" to make them and protects the coating from most things.
Is another type and most people don't understand why it matters...
This is the 1st Surface mirrors and what you see
Doesn't go thru glass Twice and doesn't "ghost" the image because of this. This is used in many cars and a lot of other things because you get a better reflection at wide angles like car outside mirrors have problem with but You can damage the mirror w/ paper towels etc.
Before anyone asks... Most Non electric Internal Rear view w/ dim tab uses both types. 100% reflective 2nd surface for day, Flip the tab and use much "weaker" 1st surface for night.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave