I don't think there is any doubt in these images being E. hecabe.

Khew, all credit to you & Sunny fot documenting and keeping a portfolio of these anomalies all these years.
Without these we will probably always have a bit of doubt in our mind as to the correct ID.
When the 1st pics were posted I thought it unlikely that E. hecabe can be completely spotless.

Do you have records of other species losing their spots?

TL Seow