If a word is truncated, either by ambient noise, an interruption, a stutter, a speech hesitation, etc, it must be transcribed as it is heard in the recording, followed or preceded by an asterisk *, depending on whether the word was truncated at the beginning or at the end.
It is CORRECT to transcribe like this:
[00:00:00] Today is a really sun*... Beautiful day.
[00:00:00] Yes, it is a [INAUDIBLE 00:00:00] *tastic day.
[00:00:00] Can we start right now, I'm pretty bu*.