Scheduled publish time changes unexpectedly

On a client site (running version 6.1.7 of scheduler) whenever a node is submitted with a scheduled publish date having "12" in the hour place, the resulting saved time ends has the incorrect "meridiem". For example, if we enter "02-27-2011 12:49 PM", then the saved time ends up being "02-27-2011 12:49 AM" (note the AM instead of PM). The inverse happens as well. If we entered "02-27-2011 12:49 AM", it would end up saving as "02-27-2011 12:49 PM". This only occurs when the hour place is "12". I briefly looked over the code and didn't see anything that stood out. Has anyone experienced this problem with scheduler module previously? Thanks.