If you are a very long way from the exchange it may be something you have to put up with. If it rains some moisture will get into the lines
Not really unless there is a fault somewhere caused by bad insulation. Its certainly not something I'd expect someone to have to put up with.
The OP does however need to check that none of the cabling/lineplant inside his own property is getting damp during the rain though as could easily be an issue within his own home.