Random Number being changed to the same number for all rows

Question

hello all,
first of all I want to mention that this problem start happening after 2.14 instalation of Power Query.
I'm creating new column in my query and setting all values to random numbers. The problem is that next step (doesn't matter what it do itself) somehow changes all those random numbers to the same random number for all lines.
here's code sample:
InsertedCustom = Table.AddColumn(RemovedColumns3, "Random Number", each Number.Random()),
    InsertedCustom2 = Table.AddColumn(InsertedCustom, "Analyst Full Name", each [Analyst First Name]&" "&[Analyst Last Name]),
when I'm checking step by step, InsertedCustom  creates new column and all values are being set randomly for all lines BUT when going to the next step (InsertedCustom2) all values in the column "Random Number" are being changed to the
same number (no matter that InsertedCustom2 itself should not be doing anything to column named "Random Number") . I even tried moving InsertedCustom step to the bottom of my code but it didn't help and still facing this issue.
p.s. updated my PQ to 2.15 - didn't help

Answer 1

This is a known issue. Power Query assumes that functions are idempotent (given the same arguments, they produce the same result), which isn't true for Number.Random. Our optimization pipeline is turning Number.Random() into a constant in the scenario you
encountered, which results in all rows having the same value.
There's been some discussion of how to fix this, but that won't help you in the near term. Can you describe a bit more about your scenario and what you're trying to accomplish? Perhaps we can help you find a workaround.
Ehren