I have set my forerunner 305 to auto-pause which is the mode which makes most sense for me.
Unfortunately there is some logic missing in the garmin software.
The software should be able to detect auto-pause waypoints and interpolate the pace between those.
Right now there is a "warp" effect e.g. if you cross an underbridge.
This is because the forerunner goes into auto-pause when it loses the satellite signal. When it receives the signal again the pace calculation just seems to divide the waypoint length difference through the auto-pause lag which results in ridiculously high speed values.
Please add some logic to the training center and garmin connect software so that those peaks are avoided.