3 columns of data not sorting by Column C times

Hi. Hope you're well. I have 3 columns of data in columns A, B, C like this (example only):

v1 v2 5:13
v3 v4 1:48
v5 v6 6:37 << should be 1st row in the sort
v7 v8 0:23
v9 v10 5:56 << should be 2nd row in this sort
v11 v12 5:38
v13 v14 3:14
v15 v16 4:27
v17 v18 1:27

The "v" are just values that not important for this question. Column C contains times, formatted as custom > h:mm. The values shown in Column C above are from a formula, if that matters. The problem is that, when I try to sort this sheet (which is only these 3 columns) BY column C (from largest to smallest values) the rows don't sort correctly. Example: the above is actually sorted, but you can see incorrectly. (3rd row above should have sorted 1st, and 5th row above should be the 2nd row, etc).

I tried converting pasting column C into another column as "values only", and then sorting by those values only column, but that didn't work either.

Thanks for helping out.

Unable to replicate. Sorting Column C largest to smallest properly sorts per your request.

Glenn/hoya, Was able to figure it out. Columns B & C had formulas, so I had to copy and paste them to a new sheet as values only. Once sorted, I changed the time values back to time format. That was pretty cool, I think.
Thank you.