That is a known issue with Google maps. The other providers don't have that issue, but IMHO Google has better maps...
That happens with me too sometimes, but if I right click and "uav -> go to uav" <pause> click + <pause> click + <pause> (repeat), it zooms in to the location.
On my field laptop I used the "Rip map" to grab all the areas I fly at at the resolutions I want, set it to cache only, and then it doesn't even have to talk to Google any more.