It might be an extra space, or a non printing character, or similar.
I blogged about a similar situation at
http://dailydoseofexcel.com/archives/2014/08/09/one-of-these-things-is-not-like-the-other/
Furthermore, there's a good explanation of non printing characters at
https://support.office.com/en-in/ar...fe5303222c9d?ui=en-US&rs=en-IN&ad=IN&fromAR=1
In regards to non printing characters, in the Unicode character set, there is an additional space character called the nonbreaking space character that has a decimal value of 160. It looks identical to a space character to you and me, but not to Excel. I've snuck a non breaking space into the text in B3 right after the 8:30 bit of text, and an you can see, it looks identical to B2.
But I've also array entered this formula into B5, that returns the string in B2 up to the point that it doesn't match the string in B3:
=LEFT(B2,MATCH(FALSE,MID(B2,1,ROW(INDIRECT("A1:A"&LEN(B2))))=MID(B3,1,ROW(INDIRECT("A1:A"&LEN(B3)))),0))
And these formulas show the character code of the underlying differing character:
=CODE(MID(B2,MATCH(FALSE,MID(B2,1,ROW(INDIRECT("A1:A"&LEN(B2))))=MID(B3,1,ROW(INDIRECT("A1:A"&LEN(B3)))),0),1))
=32
=CODE(MID(B3,MATCH(FALSE,MID(B2,1,ROW(INDIRECT("A1:A"&LEN(B2))))=MID(B3,1,ROW(INDIRECT("A1:A"&LEN(B3)))),0),1))
=160
See the attached file.
Thanks for the great question: I'm going to put a similar example into the book I'm writing.