A comparator reading from a crafter can output the wrong signal strength if the crafter is powered quickly, such as with an observer clock

Steps to reproduce:

1. place a comparator with redstone dust reading the crafter
2. set up an observer clock to power the crafter
3. block 8 slots in the crafter
4. have some items for a 1x1 recipe fed into the crafter
5. when the items run out, the comparator will still output a signal strength of 9 when it should be outputting 8