The possibles I can think of are - sun coming through water beads on the leaf; or, dirt resting on the leaf stopping photosynthesis.

The second one is the easiest to test - clean leaf and moderate light and see if it regains colour. Good luck.

(I'm watching mine like a hawk at present. Has it made enough size to flower this year??? It started out as very small and wizened several years ago and has been gaining steadily.) I'm delighted you have so many to enjoy. :-))

hi there, thanks for your anwser. im glad i havent heard its a virus, yet. this is the smallest bulb of them all. i think he is small because he was under a fatsia, i just moved the fatsia back to allow more light through. they have all flowered for me, last year i transplanted them right before bloom and the blooms were very small. so this year they will be back on track! the leaves are all dying back right now, so flowers are soon to follow!