I agree that the reporting of this has been misleading.
It's certainly volatile but a trend towards the positive could simply be interpreted as the market viewing Brexit as unlikely. Remember the bookies odds are still fairly strongly in favour of Remain, despite the vast majority of bets being for Brexit for the last several weeks. That suggests the big/smart money is on Remain.
For example, HSBC have modelled a 20% fall in GBP against USD on Brexit - they are not alone.
Hedge funds are doing their own polls and are fairly highly skilled at analysing risk.
I'd suggest that if polls continue this trend, GBP will fall in the run-up to the vote, since the potential downside looks greater than the potential upside.