C90W fix loss and stops goto waypoint

[kwf05001]

I have a C90W running version 2.20
It is using the internal GPS and is mounted on the pedestal in the cockpit below a sunbrella bimini.
I sail in Southern New England.

It intermittently loses a position fix and I get the flashing warning. I am not worried about the occasional fix loss (I understand installing a raystar antenna may reduce this problem), but am very much concerned by the fact that when a fix is lost, I lose my goto course. Why doesn't it resume following a goto once a fix is re-acquired (usually takes 30 seconds or so)?
Is this a settings issue, software issue, or design flaw?
The latest update (ver2.35) appears to only involve AIS.

Thanks for any help.