When a value with microseconds is truncated while being inserted into a time column, it does not cause a warning, as it happens in the similar situation with other data types:
Microseconds truncated, no warning:
Fractional part of a decimal value truncated, a warning is produced:
It might cause a confusion, especially if a user does not expect that the server knows about microseconds and takes them into account:
The empty result set is understandable considering that TIME is actually TIME(0), and that the inserted value is silently truncated, while in the select the string literal is converted into a temporal value with microseconds; but it is not obvious at all without a warning about truncation.