Is that {if} conditional surrounded by a Channel Entries tag, something else or nothing?
Have you tried just outputting the date in each of the {if} conditionals so something like this :
{if "{entry_date format='%U'}" < "static_date_converted_to_unix_time"}
{entry_date format='%U'} - static_date_here
{if:else}
{entry_date format='%U'} - static_date_here
{/if}
Where it says static_date_here in the code above place in the date Unix date that you have converted so you can very quickly see if the numbers you are getting output are being evaluated by the conditional correctly.
Also for now take out the assets module (I’m guessing this is the Pixel & Tonic module you’re using here?) whilst you’re testing this.
Let me know how you get on with that please.
Thanks.
Mark