For sensitive experiments, that are disturbed by cosmic radiation one can do a parallel measurement of the radiation. This is nothing new - I know it is done in some experiment, dropping data from times with high radiation background. The cosmic background is not very smooth but to a large part comes in burst. So for short intervals of something like 10 µs you get bursts of high radiation, with reasonable long time in between with much lower level. So if these high radiation times can be identified, it can be better to ignore this part of the data. There are also variations from the sun, that can be so intense that even plane avoid some regions (near the magnetic north and south poles) at some times.
Though I don't think the input stages of typical DMMs are that sensitive - this might be different when measuring in the fA range.
For the input stages of a DMM or small amplifiers I would more think of the influence of single electronic states that are either occupied or not - at effective positions these can give measurable jumps. Also the position of single dislocations can have an effect.