This has happened for a long time, but I should really file an issue, so here it is. It seems to probably happen only in Chrome, unless perhaps it is just harder to reproduce in Firefox (I wasn't able to reproduce it in FF in my testing right now, but haven't ruled it out). See NumberInput.svelte.

When you click and drag a number input field of the increment (not range) style, meaning the kind you can drag infinitely left or right, it will sometimes teleport the value to a wildly different value from the one it started with. This can be reproduced by drawing a rectangle and dragging left and right on its stroke weight parameter in the Properties panel repeatedly in quick, small left and right drags until occasionally it will make a big jump.

I hypothesize this is caused by weirdness in the event ordering and mouse position reporting with the pointer lock API, and it might be related to the widget being broken in Safari: #2038. I recommend logging the values that are being reported by the API and current state every frame to narrow down when the events occur and produce the discrepancy.

At the the 4-second mark in this video, we see it jump from 131.3 to 17.3 immediately when the click-and-drag begins: