When you chain 2 Conditional Commandblocks behind each other ,they have a giant problem of fireing multiple Times. To explain this i've made a small 4 Commandblock contraption.

First Commandblock:
scoreboard players add A vars 1

Second Commandblock:
scoreboard players test A vars 1 1

Third Commandblock:
say 1

Fourth Commandblock:
say 2

To reproduce you have to create a scoreboard and set to value to 0

When you press the button it correctly displays:

1
2

When you press it again it displays:

2

This is very annoying in fastclocks and complex mechanisms. This effect stacks so if you add another Commandblock with "say 3" The Output is:

1
2
3
2
3
3