Beats the hell out of me! Sorry
If the spots are not getting bigger or changing it may be water-type/heat damage where droplets of water sat on the plant and the sun came along and burned it.
Fungal infections can get "lumpy" too.
Bacterial infections usually get sunken.
Finally, insect damage can sometimes be perplexing as they can disappear leaving only the evidence.
It certainly doesn't look viral to me at all.
You could continue to watch it or remove the leaf(leaves) affected as long as doing so does not compromise the overall plant. Hope that helps