tylerbrown007,
Welcome to JOF
Definitely needs to be re-attached to protect against moisture intrusion.
Most gutter rails are attached with Butyl putty tape the full length behind the gutter rail, which also seals the screws. I would confirm that the screw(s) aren't stripped where the gutter came loose, and look for any signs (rusty screws, etc.) that moisture may have found it's way in.
Once the gutter section is re-attached trim off any access putty tape that you may have re-applied (if needed), then as mentioned add the matching (non-sag) RV caulk along the top of edge of the gutter rail/roof joint.
If you are still under warranty, I would take the TT to your RV dealer for a service warranty claim.
Bob
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2016 GM 2500HD 6.0L/4.10
2018 Jay Flight 24RBS
2002 GM 2500HD 6.0L/4:10 (retired)
2005 Jayco Eagle 278FBS (retired)
1999 Jayco Eagle 246FB (retired)
Reese HP Dual Cam (Strait-Line)