After 5500 miles?

I've been dropping shifts recently. Started a few weeks ago, with the snapping of a cable, replaced that and curiously, seems to be an issue shifting down into the 19 tooth cog, and up from it...(11-28 SRAM cassette) more on the downshift, it takes two taps of the lever to get it on the cog. Cable tension is good, derailleur limits are set fine...Swapped out the housing as well. New chain & cassette fyi...

5500 miles seems awfully premature to have worn out a lever. Not happy. Anyone with similar experience?