Vendor problems
 

1) Fletching Vendors
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The fletching vendors in Kelethin/Surefall Glade/Elsewhere don't have the items that they should be selling.

Kelethin merchants are missing Fletchings, Surefall Glade merchants miss on Arrowheads and such. They should have all the materials to level up the skill. Multiple of them.

The only merchant so far that I found to be having ALL of the required fletching materials (except those for making bows) is the vendor in East Commonlands.

2) Vendors in general
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It seems that if you sell enough junk, you can push the regular vendor's sell-listed-items off of the chart effectively making the vendor only sell junk. Zoning out/logging doesn't seem to solve the problem (probably since the vendor isn't client-side anyhow).
Spell vendors are such example, same with fletcher vendors.

Please fix in some near future.

What server are you playing on? And do you know if their database is current?

If they're using the PEQ database, then reports like this and the one about the Trueshot Longbow quest should be submitted over at their forums.