In the Standard Units environment, the global verify function is replaced by a verify function that converts any unevaluated arithmetic operators, equalities, or inequalities to their global equivalents.

For more information about this function, see the global verify help page.

verify(3.50000003 = a, 3.499999997 = a, 'float(100) = boolean');

$\mathrm{true}$

with(Units[Standard]):

:-verify(3.50000003 = a, 3.499999997 = a, 'float(100) = boolean');  # unexpectedly false

$\mathrm{false}$

verify(3.50000003 = a, 3.499999997 = a, 'float(100) = boolean');

$\mathrm{true}$