From the 8085 CPU architecture, when ALU done calculation, the result is clocked back to accumulator A on next clock edge. But accumulator A is directly wired as ALU input, what if the clock edge didn't raise fast enough to cause A is being added twice or many more times, it would be extreme difficult to detect such an error, such a design is very "fragile" to me.
Unless, there is an extra register within ALU to temporary save ALU results?
https://en.wikipedia.org/wiki/Intel_8085#/media/File:Intel_8085_arch.svg