Garmin upload - wrong date?

Twice in the past few days, BT seems to think a workout on my Garmin is on the wrong day. I wrote the first one off as a fluke and entered it manually, but now it is clear something is up. I had a running workout this morning, and BT found no running workouts today (Garmin TC and SportTracks both uploaded correctly). I backed up a day in my log, and it found a running workout yesterday (I had none, only a cycling workout). Time and lap data appear to be right, only date is one day off.

Anyone else ever seen this? I've been uploading correctly for like a year without an issue, and I don't think I changed any settings. Ron/Marma help?