RTC 4+ digit durations error as "not a positive number?"

Hi,

I'm trying to enter a value, in seconds, into a field of type "Duration." The value is 28800, the unit of time is seconds. I receive a little red x on the field with the message that "28800" is not a positive number, rather than converting the number to a combination of hours and/or minutes and/or seconds. If I enter 999 seconds, the value shows up as 16m 39s. Any value of 4 digits or higher errors out as not being positive. Obviously I could just convert to a different unit of measurement and get the value under 4 digits, but I'm also running imports and this is causing errors. I have also never seen this before in the 4+ other project areas I have imported data to. Any insights? I also have a few screenshots...

4 Digit Value:

Error Message when mousing over field:


Entering a 3 digit value causes no problems:


Thanks,
- Josh

Edit: Clarification