comparator output doesn't work fine with command blocks

In 1.15.2 if a command block with this command

• execute if @a[xyz] (so count the number of players in a certain area)

is connected to a comparator the redstone output is always 1 even if there are more player in these area

For example if there were 3 players the redstone signal created by the comparator should be 3 blocks.

In 1.14  it worked. 

Thanks for your attention.