ITA experts out there - what's going on here?

I'm trying to nab this fare that I've been carefully watching. ITA is pricing it at $273, but when I try to book on Delta.dumb - it comes in at $473.

On ITA it's a mixed V-U class flight - on dl.com it's coming back as T-U... This has actually been going on for the past 2 days on ITA. I even tried to push this to Americanexpress.com, but it's unable to ticket. Orbitz, Kayak, etc. are not showing this fare.

St Louis (STL) to Hartford (BDL) - Tue, Jun 18
St Louis (STL) to Minneapolis/Saint Paul (MSP) - Tue, Jun 18
Delta 1544 Dep: 5:00PM Arr: 6:40PM 1h 40m MD-80 Economy (V)
Layover in MSP 0h 35m

Minneapolis/Saint Paul (MSP) to Hartford (BDL) - Tue, Jun 18
Delta 1274 Dep: 7:15PM Arr: 10:53PM 2h 38m MD-90 Economy (V)


Hartford (BDL) to St Louis (STL) - Mon, Jun 24
Hartford (BDL) to Detroit (DTW) - Mon, Jun 24
Delta 1808 Dep: 7:15AM Arr: 9:17AM 2h 2m MD-80 Economy (U)
Layover in DTW 3h 8m

Detroit (DTW) to St Louis (STL) - Mon, Jun 24
Delta 3565 Dep: 12:25PM Arr: 1:04PM 1h 39m Canadair RJ 900 Economy (U)
OPERATED BY PINNACLE DBA DELTA CONNECTION
Cost per passenger (including taxes & fees) $272.60
Total cost for 1 passenger $272.60