What a load of bunkum.
No such thing happens. Whilst it is recommended to power cycle (turn
off/on)your phone regularily, at least once a week or preferably once a
day to refresh the phone's software, your phone will always sit on the
nearest cell or cells and will always call the nearest available cell
to make or receive a call.
The only variation to this is that if you are roaming in one country,
the network will remember which country you were last in, if you turn
off your phone, until you turn your phone on in another country.
Eventually if the phone isn't turned on for a while the network memory
will time out and return your phones routing back to your home country.