Landscaper put in new patio of quartizite flagstone with mortar joints in winter. After el nino rains some of the mortar is cracking in areas where the stones were dry laid (no concrete base). some gaps are almost a credit card wide. Is it best to just reapply mortar to these cracks or do we need to do more? will this tend to return or worsen with wet/dry season cycles? we are in northern california.

thanks