That's one of the issues. The other is the disappearing breadcrumb trail that can happen any time. With mine it made navigation next to impossible since the track would disappear randomly and usually just as I was approaching a turn. Since I moved to a new area and needed my Garmin to navigate new routes I sold it (for £5 less than I paid for it 2 years earlier - used Garmin prices are insane) and bought an Edge 800.
This is the same point I was making.
However I found that courses under 40 miles were fine, anything over that then it disappeared as you say.