Updated 14-10-2014 see solution at the end.
Updated 17-07-2015 Bug no longer present in version 10.2
This answer is basically for documentation of the problem.
The credit goes mainly to the people participating in the comments.
Diagnostics
I can reproduce you observation on two different computers both, Windows 7 Pro 64, SP 1 running Mathematica 10.0.1. The "feature" appears for list of 11 or more random numbers, both using RandomReal
and RandomInteger
. I can NOT reproduce the problem on same computer but running Mathematica 9.0.1, so it may be a new bug.
These are my tests:
Mathematica 10.0.1
list = RandomInteger[100, 11]
{32, 93, 57, 54, 52, 43, 75, 72, 76, 0, 22}
list == %
False
list
{55, 35, 91, 46, 90, 69, 4, 65, 98, 49, 27}
list2 = RandomReal[100, 12]
{4.74866, 2.96541, 45.1146, 51.7122, 15.335, 24.3059, \
55.6953, 9.82313, 39.6287, 7.48303, 11.8829, 65.0989}
list2 == %
False
list2
{72.6577, 86.4083, 24.7092, 93.0095, 66.7453, 20.361, \
0.751391, 54.1193, 93.568, 7.31844, 93.3521, 21.871}

No difference for shorter lists
list = RandomInteger[100, 10]
{3, 93, 60, 7, 95, 22, 60, 99, 96, 12}
list == %
True
Also no problem if evaluated in the documentation notebook

Mathematica 9.0.1
list = RandomInteger[100, 100]
{40, 4, 94, 60, 85, 10, 91, 74, 4, 30, 88, 29, 46, 36, 13, 79, 52, 96, 71, 18, 20, 13, 36, 62, 98, 48, 88, 20, 92, 75, 6, 92, 11, 90, 85, 5, 66, 35, 21, 57, 69, 86, 20, 91, 18, 94, 100, 74, 37, 1, 8, 86, 14, 79, 43, 78, 30, 0, 3, 16, 94, 95, 27, 68, 56, 51, 33, 80, 62, 69, 60, 45, 70, 61, 30, 59, 37, 97, 29, 97, 14, 23, 8, 10, 99, 23, 36, 75, 83, 8, 31, 97, 89, 31, 90, 5, 56, 71, 80, 67}
list == %
True
Cause
I have contacted Wolfram Technical Support and in their reply they say:
This is indeed a serious problem and from my testing it looks like
this happens when the predictive interface is turned on. This at the
moment seems to be a front-end issue
Solution
This is a bug, so there is no solution for v10.0.1. Based on the answer from Wolfram Technical Support and the comments by @Square1 and @Naitree a temporary workaround is to disable or minimize the suggestion bar feature.


Random*
functions for the 1D case but not the multidimensional list generation, except forRandomColor
where it also affects the multidimensional case. I'm on Windows 10 TP. $\endgroup$