On our visit between Christmas and New Year's, there were those immediate returns (5 minutes out) at TOT for a little while and for Star Tours at least a few hours after the park opened. I really don't think it was a technical glitch. I think it was just a reflection of the fact that not many FPs for the attraction had been issued.
We were going to get in the standby line for Star Tours because the posted wait was 20 minutes, but when we saw that the FP return was only 5 minutes out, we pulled out our APs, got a paper FP and went right into the attraction. There was virtually nobody else in the FP line so we were waved right into the boarding area.
There are three reasons why people would get into a standby line with FP returns like this: (1) they may have been staying at one of the resorts that weren't issuing KTTW cards and didn't have access to paper FP, (2) they were already holding a paper FP for something else (like TSMM or RNRC) and couldn't get another one yet, or (3) they didn't know any better.