The bug

Modifier stages of a command decrease command quota even if they are not executed. This causes the command quota to be consumed in a counterintuitive manner.

How to reproduce

1. /scoreboard objectives add mc-266388 dummy

2. /gamerule maxCommandChainLength 3

3. /scoreboard players set # mc-266388 0

4. /function mc-266388:f

   → A is printed. This behavior would be correct; the function call and execute if score # mc-266388 matches 1 each consumes 1 command quota, leaving 1 for say A.

5. /function mc-266388:g

   → A is not printed. This behavior might be incorrect; the function call, execute if score # mc-266388 matches 1, and the second if score # mc-266388 matches 1, which is not executed in this case, each consumes 1 command quota, leaving 0 for say A.

execute if score # mc-266388 matches 1 run seed
say A

execute if score # mc-266388 matches 1 if score # mc-266388 matches 1 run seed
say A