A bent thumbscrew on these inside micrometers is apparently a “feature:” the used Starrett 1” - 2” I brought 2 years ago had the same issue. Like yours, the screw was straight, so I removed it and some gentle tapping corrected the problem (I get a spare the next time I ordered parts from Starrett just in case). The micrometer itself was in perfect condition:
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(Box is new; the mic came in the original box)
Of course, I then bought a 1.2” (-ish) Setting Ring Amazon) so I could calibrate it (the cycle never stops):
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