Random date in "start_time"

Hi,

Got a site that now have some wrong build of "start_time" where a few lines have an added "date" of "31/12/1899" and seconds within. This causes the scrubbing to fail overall.

Wrong format: "start_time":"31/12/1899 18:30:00"
Right format: "start_time":"23:00"

How can I remove this fixed date from those "start_time" lines that have it?
Also need to fix/remove the seconds from this timestamp: 18:30:00 >> 18:30

From INI:

index_variable_element.modify {set|'config_site_id'}
index_showsplit.scrub {multi|{"name":"'index_variable_element'","data":[|{|}|]}}
*
index_temp_1.scrub {single|"date":"||"|"}
index_start.scrub {single|"start_time":"||"|"}
index_start.modify {addstart|'index_temp_1' }

Brgds
Strilen