I have that 0.8 sec time lag from an inspection by @Dean_Z.
Z1 used to have an issue with timing too. I do not not know if it ever got resolved. @Shotaro_Igami knows.
Those Google frame rate recommendations have been there all along in their Help system. The lower frame rates just avoid an excess of imagery, taking the camera movement speed into account. They save on needed stitching, battery, storage, upload and Google processing.
That year ago @Sam_Rohn position quality test was walking along a sidewalk in New York. The trace showed many anomalies. Likely caused by buildings on one hand blocking signals and signal reflections from buildings too. The usual city canyon issue. Of course those situations exist in mountainous nature too.
I feel camera manufacturers should get more serious on selection of antenna and fused GNSS / Inertial Measurement Unit module, as well as the tuning thereof, exposing usefull settings too.