it appears the numeric input is “skipping” numbers. for me it randomly jumps from zero to two, or only increments odd numbers. it appears to be pretty random.
i see this same behavior on firefox-113, chrome-113m safari, and edge testing with browserstack.com
it just seems to intermittently skip certain numbers. this MAY have something to do if you click “near” the arrow rather than right on the arrow, but i have yet to find a pattern.