Attribute error when using GbmDetectorCollection with TTE data: cannot find detector information

[OliverRoberts-USRA]

When I convert TTE data to PHAII or PHA files and group several detectors using GbmDetectorCollection, there seems to be missing values for local arguments. This procedure works for other PHAII types like CTIME and CSPEC. I tried converting to PHAII and then to PHA and I get the same error during the conversion to PHA. May it is an issue specific to the opening/reading of TTE files and converting them to PHAII/PHA? Might be related to issue #13?

When converting directly to PHA from TTE: