Beyond the unarguable issues noted above re lack of warnings, misuse of the array and the while...
as the regex itself is written, you have three captures, (.*), (the digits and colons) and (any_old_junk lazily).
Since the digits capture is greedily quantified, it could match on variant data: (for example: 243:4321:78654321) that was not actually part of a datestamp.

...So it might be well to assure yourself that item is formatted as datetime

[A-Z][a-z]{2} [A-Z][a-z]{2}\s\s?\d\d?: 
             ^exactly 1 space  ^one or more spaces,
[download]

or somesuch....