Gunner,
Get used to it, it's the nature of the beast.
Kydex should come with a warning label that reads "To be used for USING KNIVES ONLY! that you don't mind getting scratched!"
Sounds like sand has gotten into your sheath. Disassemble if possible and clean the inside of the sheath out. If disassembly is not possible, I run a coupla gallons of soapy water thru mine and rinse thoroughly. That usually does it for my kydex sheaths.
GOOD LUCK!
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The choices we make dictates the life we lead.