K (ngn/k), 9 bytes

Solution:

~=':,/+2\

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Explanation:

~=':,/+2\ / the solution
       2\ / convert to base 2
      +   / transpose
    ,/    / flatten
 =':      / equal to each-previous?
~         / not

K (ngn/k), 9 13 bytes

Solution:

~=':,/(7#2)\'

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Explanation:

~=':,/(7#2)\' / the solution
           \' / convert each
      (   )   / do this together
       7#2    / 2 2 2 2 2 2 2
    ,/        / flatten
 =':          / equal to each-previous?
~             / not

Notes:

• +4 bytes to support strings consisting only of 6-bit chars

K (ngn/k), 9 bytes

~=':,/+2\

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On mobile, explanation to follow.

K (ngn/k), 9 bytes

Solution:

~=':,/+2\

Try it online!

Explanation:

~=':,/+2\ / the solution
       2\ / convert to base 2
      +   / transpose
    ,/    / flatten
 =':      / equal to each-previous?
~         / not