In src/libs/zbxserver/evalfunc.c add_value_suffix_normal() uses the following expressions to check if a value has no fractional part:

if (SUCCEED != zbx_double_compare((int)(value_double + 0.5), value_double))

Converting double to int may cause overflow and lead to unexpected results.

A more delicate way of doing the same thing:

if (SUCCEED != zbx_double_compare(round(value_double) - value_double, 0.0))