The GARDENA gardening expert
Dear Mr. S., regarding your first question:
The grain patterns could be a virus infection, caused by the raspberry mosaic virus. Please compare the appropriate google images with your observed damage symptoms.
A nutrient deficiency may also be a reason, however, I would have to examine the plant more closely to assess the leaves. Yellow discolouration between the leaf veins can indicate an iron deficiency.
However, the cause can also be a lack of micronutrients, which however occurs more rarely and which can be remedied through balanced doses of compost or, if required, speciality micronutrient fertiliser. Iron deficiencies occur more frequently, because they are generated when the soil in which the raspberries are planted is not acidic enough (e.g. in calcareous soil or if they are supplied with very calcareous water – citrus plants and rhododendrons are also susceptible to this problem).
As to your second question:
The damage pattern you have described is familiar to me from my own raspberry plants, but it cannot be traced directly back to one single damage factor. It occurs, for example, when the raspberry beetle larvae eat in particular the initial ripening partial fruits of the multiple fruit.
These first parts of the fruit or the eaten upper ring will die off. The damage can be even more clearly observed if fungal infestation also attacks these parts, which occurs frequently (grey-green fungal coating). However, I also suspect a physiological ripening defect due to the changeable, damp and warm weather conditions.