These weeks I've noticed Weird Things going on with my GPS:

osm.org/user/mbethke/traces/1029314

If you compare this with the satellite image and previous traces, you'll see the track is shifted several dozen meters northish.
Has anyone seen a GPS unit break in this way before? I don't have another GPS here to compare. This is a qstarz BTQ-1000X that has always been pretty amazing in sensitivity and exactness ...